Space Invaders · mimo-v2.5

Let me build a Space Invaders-style game in a single index.html file. I'll write procedural graphics (canvas drawn shapes), no external assets.

Plan:
- Canvas 800x600 or so.
- Player cannon at bottom, moves with arrows/A/D, space fires, fire rate cooldown, projectile lifetime bound.
- Alien grid 5x8 or 6x11, moves horizontally, descends at edges, speeds up as fewer aliens.
- Aliens fire projectiles toward player (random alien from bottom of column fires, roughly aimed with slight horizontal velocity toward player).
- Bunkers: 3-4 bunkers, made of small cells (grid of blocks), drawn as a shape with an arch. Damage removes cells; shots pass through gaps.
- Lives: 3, invulnerability period after hit (flash). Game over when lives 0 or aliens reach player zone. Win when all aliens dead.
- Restart button restores everything.
- Score display, lives display, controls display.
- States: 'start' (press key to start?), playing, gameover, win.

Let me write it carefully and then test with browser tools.

Key implementation details:

Aliens: grid cols=10, rows=5. Each alien type by row: rows 0: 30 pts, rows 1-2: 20, rows 3-4: 10. Alien size ~34x24, spacing44x34. Formation width = 10*44 = 440. Start x offset centered.

Alien movement: move as a group with direction; when edge reached (group bounding box hits wall), reverse and descend. Speed increases as aliens are destroyed: speed = base * (1 + (1 - aliveCount/total) * something), or step-based: move in discrete steps like original. I'll do smooth-ish movement: group x advances each frame by dir * speed, speed depends on remaining count. Also animate alternate frames.

Alien firing: every fireInterval (decreasing with difficulty), pick a random column that has a living alien, take the bottom-most alien in that column, spawn shot. Aim: velocity toward player with slight horizontal component: vx = clamp((player.x - a.x)/something, -maxVx, maxVx), vy = base speed. Add slight randomness.

Player shots: one at a time? Original allows one shot at a time; spec says "Bound projectile lifetime and fire rate" — so fire cooldown e.g. 250ms, max lifetime ~2s. Allow multiple shots on screen (cooldown limits). I'll allow up to... just cooldown 300ms.

Collision: shot vs alien (rect), shot vs bunker cells, enemy shot vs bunker cells, enemy shot vs player, player shot could also hit enemy shot? Not needed.

Bunkers: 3 bunkers (maybe 4). Each bunker: cell grid 12 cols x 9 rows, cell size 5px → 60x45. Shape: rectangle with arch cut at bottom center, plus angled top corners. Represent as 2D array of 1/0. Damage: on hit, remove cells within a radius of hit point (circle radius ~9px), for incoming-from-top hits remove upper chunk, from bottom remove lower chunk — simple: remove cells in radius, plus make it look eroded. Persistent.

Draw bunkers: draw each remaining cell as rect of color green, slightly merged look — draw with fillRect per cell, and maybe use path. Simpler: draw cells individually with small gaps removed — actually just fillRect each cell with same color gives contiguous look.

Explosion particles: procedural — particles array for explosions.

Star background: static procedural stars, maybe twinkling.

Sounds: could use WebAudio procedural beeps. Optional, nice. Keep simple: small oscillator blips with a toggle? Might cause autoplay issues — AudioContext created on first user interaction (keypress). Fine, include a mute toggle. Keep it simple but safe: create AudioContext lazily on first input.

Controls display: on-screen text at bottom of HUD.

Restart button: HTML button + also 'R' key.

Canvas rendering: use requestAnimationFrame with dt clamp.

Invulnerability: after losing a life, player respawn with2s of flashing invulnerability, clear enemy shots near player maybe.

Aliens reaching player zone: alien bottom y >= player.y - some margin → game over.

Score feedback: score popup text that floats and fades at hit position.

Let me also implement particle explosion when alien dies, and screen shake maybe.

Let's write the file. Size moderate (~700-900 lines). Then test in browser: check console for errors, screenshot, simulate keypresses (move, fire), verify bunker damage and score, click restart, verify reset.

Testing with browser tool: use key action to send ArrowLeft etc. Check state via inspect (evaluate JS?). The browser tool has "inspect" action which likely dumps DOM/console. I can also expose window.__game = state for inspection. Let me expose `window.game` with reference to state object so I can inspect via... hmm, inspect action may just give DOM snapshot and console logs. I can log state to console at intervals or on demand. Alternatively use `console.log` from injected click... The browser tool actions: reload, inspect, screenshot, motion, click, drag, key, type, scroll. No evaluate. So I'll rely on console logs — I can have the game log key events to console (or use a debug logging toggle). Simpler: I'll add console.log on start, alien killed (score), bunker hit (maybe throttled), life lost, game over, restart. That gives visibility in console inspection.

Let me write the code.

Details of drawing:

Player cannon: procedural drawing — body with base and barrel, cyan/green. Draw using path: treads base rect, body trapezoid, barrel rect on top. Plus slight thruster glow.

Aliens: three types drawn procedurally with rects/pixels — draw as pixel-art via small square grid patterns per type, with two animation frames. Define patterns as arrays of strings. That's a neat procedural approach (no external assets). Pixel size ~3px.

Type A (squid, 30pts) 8x8 pattern; Type B (crab) 11x8; Type C (octopus) 12x8.

Let me define patterns:

Squid (8 wide):
```
..XX..  -> hmm squid is 8x8
```
Classic sprites:

Squid frame1 (8x8):
```
...XX...
..XXXX..
.XXXXXX.
XX.XX.XX
XXXXXXXX
..X..X..
.X.XX.X.
X.X..X.X
```
frame2:
```
...XX...
..XXXX..
.XXXXXX.
XX.XX.XX
XXXXXXXX
.X.XX.X.
X......X
.X....X.
```

Crab (11x8) frame1:
```
..X.....X..
...X...X...
..XXXXXXX..
.XX.XXX.XX.
XXXXXXXXXXX
X.XXXXXXX.X
X.X.....X.X
...XX.XX...
```
frame2:
```
..X.....X..
X..X...X..X
X.XXXXXXX.X
XXX.XXX.XXX
XXXXXXXXXXX
.XXXXXXXXX.
..X.....X..
.X.......X.
```

Octopus (12x8) frame1:
```
....XXXX....
.XXXXXXXXXX.
XXXXXXXXXXXX
XXX..XX..XXX
XXXXXXXXXXXX
...XX..XX...
..XX.XX.XX..
XX........XX
```
frame2:
```
....XXXX....
.XXXXXXXXXX.
XXXXXXXXXXXX
XXX..XX..XXX
XXXXXXXXXXXX
..XXX..XXX..
.XX..XX..XX.
..XX....XX..
```

Good enough.

Alien colors by row: rows 0 → #ff5d7a? Classic: top row pink/red, middle cyan, bottom green. I'll use: row0 #ff6ec7 (magenta), rows1-2 #5ad1ff (cyan), rows3-4 #7dff6b (green).

Player: #6bff8f.

Enemy shots: drawn as small zigzag/bolt, red-orange with glow, animated.

Bunkers: #3ec46b.

HUD: score white, lives as small cannon icons.

Game states: 'title' (awaiting start? Spec doesn't require a title; but showing "press space" start screen is fine). Actually let's start immediately in 'playing' on load? Requirement: "Test movement and firing during the opening formation" — start playing immediately after load is easiest for verification. I'll start in 'playing' state directly, with aliens moving. Game Over/Win overlays with Restart button + R/Space restart.

Fire rate: cooldown 280ms; max player shots maybe 3 concurrent — fine.

Projectile lifetime: player shot lives max 2.2s or until off-screen; enemy shot max 4s.

Movement speed: player 320 px/s. Alien group speed: base 28 px/s * multiplier. Speed increases as aliens die: speed = (24 + (1 - alive/total) * 90) * levelMultiplier. Also when all remaining aliens... fine.

Alien descent: 24px.

Alien drop of "bombs": fire timer random0.5–1.6s scaled by alive count.

Bunker geometry: playfield width 860? Canvas 900x640. Let's do canvas 900x640. Playfield margin 20px sides.

Bunkers: 3 bunkers, each width 88, height 56, cells 8px? Let's do cell4px with grid 22x14 → 88x56. Hmm, more cells = finer erosion. cell5px, grid 18 cols x 11 rows → 90x55. Bunker shape: full rect with bottom-center arch (semicircle radius ~5 cells) removed, top corners chamfered.

Positions: 3 bunkers centered between x=120..780 spaced evenly. Playfield width 900, margins 20. Available860. 3 bunkers width 90 each = 270, gaps: place centers at 25%, 50%, 75% of playfield → x centers 225, 450, 675.

Player y: bottom at 610 (playfield bottom 620?). Let's set canvas 900x640, play area y from 40 (HUD) to 620. Player y (top of cannon) = 572, cannon height 26 → bottom 598. Bunkers sit above: bunker bottom at ~540. Alien zone: game over when alien bottom >= 552 (above bunkers-ish/player). Actually "Aliens reaching the player zone" — when lowest alien's bottom >= player top - 6 or crosses bunker line. I'll use y >= 545.

HUD at top: score, high score, lives, controls text. Controls displayed: "← → / A D move · SPACE fire · R restart".

Drawing pixel sprites: function drawSprite(pattern, x, y, px, color, flip?) — fillRect for 'X'.

Explosion particles: array of {x,y,vx,vy,life,color,size}.

Score popups: {x,y,text,life}.

Screen shake: small, on life loss / big explosion.

Starfield: 90 stars with random positions, sizes, twinkle phase.

WebAudio: simple beep function using oscillator; muted default? Sound on by default but context resumed on first keydown. Provide 'M' to mute. Keep it small.

Now collision detection:
- Player shot rect (3x14) vs alien rect.
- Shot vs bunker cells: compute cell indices under shot rect; on hit remove cells in blast radius and destroy shot.
- Enemy shot vs player rect: if not invulnerable.
- Enemy shot vs bunker cells (blast from below).
- Also player shot could pass through gaps — automatic since cells removed.

Bunker blast radius: for hits, remove cells within radius r=2.2 cells of hit cell, with a random mask to look eroded. Implement removeBunkerCells(bunker, cx, cy, radius): for each cell within distance, remove with probability based on distance (closer = sure).

Also alien bodies erode bunkers when descending into them? Nice touch: if alien overlaps bunker, remove cells. I'll add that — aliens colliding with bunker erode material persistently. Keep simple: if alien rect overlaps a filled cell, remove that cell. That's classic behavior. Then game over check follows.

Let's write everything now.

Also need "Display the controls" — yes, HUD line.

Restart restores: aliens (new formation), bunkers (rebuild), score 0, lives 3, player centered, state playing, enemy shots cleared, player shots cleared.

Let me write the HTML file.

Code structure:

```js
const canvas = document.getElementById('game');
const ctx = canvas.getContext('2d');
const W = 900, H = 640;
const PLAY = { left: 20, right: 880, top: 44, bottom: 620 };

let state = 'playing'; // 'playing' | 'over' | 'win'
let score = 0, lives = 3, hiScore = ...
```

Keys: object keys down. keydown handler: preventDefault for arrows/space. Space in over/win state → restart. R always restart.

Alien formation object:
```js
const aliens = { cols: 10, rows: 5, cw: 46, ch: 34, x0, y0, dir: 1, list: [] }
```
list entries {col,row,x,y,type,frame,alive}.

Formation movement: compute min/max x of alive aliens each frame; if max + speed*dt beyond right edge → dir=-1, descend. To make it move cleanly, move group by offset: keep formation.x and formation.y and alien positions relative (col*cw, row*ch). That's cleaner: alien screen pos = formation.x + col*cw + rowOffset... Let's do formation.x/y as top-left of grid, alien screen pos = formation.x + col*cw, formation.y + row*ch. Bounding: leftmost alive col, rightmost alive col.

Update:
```
let minX = formation.x + minCol*cw;
let maxX = formation.x + (maxCol+1)*cw;
if dir>0 && maxX + step > PLAY.right → dir=-1, y += descend
else if dir<0 && minX - step < PLAY.left → dir=1, y += descend
formation.x += dir*speed*dt
```
Where step = speed*dt.

Alien fire: timer; pick random alive alien that is bottom-most in its column. Compute vx toward player: (player.x - a.x) * 0.35 clamped to ±90, vy170–220. Hmm, aiming "toward the player" — good.

Player shots speed: -420 px/s. Enemy 180 px/s downward.

Fire cooldown 0.28s; also cap onscreen player shots at 4.

Player invulnerability: after hit, invuln = 2.0s, player flashes; also clear enemy shots in a radius? Just make invuln.

Also brief "protection from repeated damage" — invuln 2s. Also maybe alien shots near respawn cleared. I'll clear all enemy shots on life loss to be safe/fair.

Game over when lives0 or alien reaches zone.

Win: no aliens alive → state 'win', bonus score maybe.

Rendering overlay for over/win: translucent panel with text + "Press R / SPACE or click Restart".

Restart button: an HTML button below canvas in the page, styled with CSS. Also drawn in canvas? Use HTML button — simpler and clickable via browser tool. Add a Mute toggle button too. Place them in a bar under canvas along with controls text.

Let me now write it.

For performance, draw bunkers by iterating cells; bunker grid 18x11 = 198 cells * 3 = ~600 fillRects per frame — fine.

Now write the file. I'll be thorough but concise.

Let me write code fully.

```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Procedural Invaders</title>
<style>
  :root{ color-scheme: dark; }
  body { margin:0; background:#05070f; color:#cfe; font-family: ui-monospace, Menlo, Consolas, monospace; display:flex; flex-direction:column; align-items:center; min-height:100vh; }
  h1 { font-size: 18px; letter-spacing: 4px; margin: 14px 0 8px; color:#7dff9d; text-shadow:0 0 12px #2f8f4a; }
  #wrap { display:flex; flex-direction:column; align-items:center; gap:10px; padding-bottom:24px; }
  canvas { background:#05070f; border:1px solid #1d2b45; border-radius:8px; box-shadow:0 0 40px rgba(60,200,120,.12); }
  #bar { display:flex; gap:12px; align-items:center; flex-wrap:wrap; justify-content:center; font-size:13px; color:#8fb; }
  button { font: inherit; ... }
</style>
</head>
```

JS in script tag. Let me write the whole thing in the write call.

Sound helper:

```js
let audioCtx=null, muted=false;
function beep(freq, dur, type='square', vol=0.05, slide=0){
  if(muted) return;
  try{
    if(!audioCtx) audioCtx = new (window.AudioContext||window.webkitAudioContext)();
    if(audioCtx.state==='suspended') audioCtx.resume();
    const t=audioCtx.currentTime;
    const o=audioCtx.createOscillator(), g=audioCtx.createGain();
    o.type=type; o.frequency.setValueAtTime(freq,t);
    if(slide) o.frequency.exponentialRampToValueAtTime(Math.max(30,freq+slide), t+dur);
    g.gain.setValueAtTime(vol,t); g.gain.exponentialRampToValueAtTime(0.0001,t+dur);
    o.connect(g); g.connect(audioCtx.destination); o.start(t); o.stop(t+dur+0.02);
  }catch(e){}
}
```

Now full game logic. Write it.

Bunker creation:

```js
const B_COLS=20, B_ROWS=12, B_CELL=4.5; // 90 x 54
function makeBunker(cx, bottomY){
  const grid=[];
  for(let r=0;r<B_ROWS;r++){ grid.push(new Array(B_COLS).fill(0)); }
  for(let r=0;r<B_ROWS;r++){
    for(let c=0;c<B_COLS;c++){
      // chamfer top corners
      const chamfer = 3;
      if(r < chamfer && (c < chamfer-r || c >= B_COLS-(chamfer-r))) { grid[r][c]=0; continue; }
      // bottom arch
      const acx=(B_COLS-1)/2, archR=4.2;
      const dy = B_ROWS-1-r;
      const dx = c-acx;
      if(dy < 4 && Math.sqrt(dx*dx*1.4 + dy*dy*2.2) < archR) { grid[r][c]=0; continue; }
      grid[r][c]=1;
    }
  }
  return { x: cx - B_COLS*B_CELL/2, y: bottomY - B_ROWS*B_CELL, grid };
}
```

Hmm arch: use ellipse: (dx/5.5)^2 + (dy/3.2)^2 < 1 → removed for bottom rows. Let me do: if(dy<=3 && Math.pow(dx/6,2)+Math.pow((dy-0.5)/3.5,2) < 1) removed. Fine — I'll tune visually via screenshot.

Bunker hit:

```js
function bunkerHit(b, px, py, radius){
  const c0 = Math.floor((px-b.x)/B_CELL), r0=Math.floor((py-b.y)/B_CELL);
  let removed=false;
  for(let r=r0-3;r<=r0+3;r++) for(let c=c0-3;c<=c0+3;c++){
    if(r<0||c<0||r>=B_ROWS||c>=B_COLS) continue;
    if(!b.grid[r][c]) continue;
    const dx=(c+0.5)*B_CELL+b.x-px, dy=(r+0.5)*B_CELL+b.y-py;
    const d=Math.hypot(dx,dy);
    if(d < radius*(0.7+Math.random()*0.6)){ b.grid[r][c]=0; removed=true; }
  }
  return removed;
}
```

Shot vs bunkers: find first bunker where shot rect intersects bbox and a filled cell intersects shot rect. For each shot, check cell under its center; if filled → hit at that point.

```js
function shotHitsBunker(b, sx, sy, sw, sh){
  const c0=Math.floor((sx-b.x)/B_CELL), c1=Math.floor((sx+sw-b.x)/B_CELL);
  const r0=Math.floor((sy-b.y)/B_CELL), r1=Math.floor((sy+sh-b.y)/B_CELL);
  for(let r=r0;r<=r1;r++) for(let c=c0;c<=c1;c++){
    if(r<0||c<0||r>=B_ROWS||c>=B_COLS) continue;
    if(b.grid[r][c]) return {x: sx+sw/2, y: sy+sh/2};
  }
  return null;
}
```

Alien erode bunker: for each alien, for bunkers, check cells overlapping alien rect and remove a few.

OK. Score popup on alien kill: `pops.push({x,y,text:'+'+pts,life:0.9})`.

Now write it all out.

Also draw lives icons, score, hi-score, wave, and a progress note. Include "controls" text on canvas too (HUD line): "◀ ▶ / A D  MOVE    SPACE  FIRE    R  RESTART". 

Let me write the file now. Then test.

Regarding browser test: viewport 1200x800, canvas 900x640 + header/buttons may overflow slightly — total height ~ 24 (h1) + 640 + 40 ≈ 730, fits in 800. Good.

Now write.

Now run it in the browser and inspect.

The game renders nicely. Issues visible:
1. The cannon is drawn too low — it's overlapping the bottom area, and appears cut off at the bottom edge (player.y = PLAY.bottom - 34 = 620-34 = 586; cannon height ~22 plus barrel above → bottom at 586+19=605, ground line at 608). Looks okay-ish but the cannon appears to hang below the ground line. Actually in the screenshot the cannon sits below the ground line. The cannon bottom is at 605, ground line at 608 — hmm, in the image the ground line is at y≈666 (screen coords include canvas offset ~44 + scale). The cannon at screen y≈615-652, ground line at ~666. Actually the cannon looks fine, just above the line. Hmm, the screenshot shows the cannon at y≈620-650 and ground line at 666 — so it's above the ground line. OK fine.

2. LIVES display: shows only 2 icons because one life is "in play". Might be confusing — HUD shows 2 spare icons. It's fine but maybe better to show all 3 with the current one indicated. Actually the classic approach: show remaining lives as icons =2 spare. The requirement: "Start with three lives." Showing 2 icons could look like 2 lives. Let me change to show lives count icons (all 3) or label "LIVES ×3". I'll draw `lives` icons — clearer. Change: draw icons for i < lives.

3. Bunkers look decent.

4. Aliens: formation looks good.

Let me check movement, firing, bunker damage, score. Use key presses. The browser "key" action sends a key; I need hold-down for movement. The key action probably does keypress/keydown+keyup. A single keydown/keyup for ArrowLeft will move only one frame. Better: I can test via pressing space (fire) and check shots count. For movement, hold via repeated key events — the harness may support a single key press only. Alternative: check with multiple key actions quickly, but each keydown+keyup pair moves player by speed*dt which is tiny.

Hmm, I could add a fallback: also allow clicking on canvas? No. Better approach for testing: simulate sustained input by sending many key events. If each `key` action delivers a keydown without keyup until next... uncertain. Let me test: send key ArrowRight and inspect player x before/after with a delay.

Actually I can't evaluate JS via browser tools other than inspect (console + dom). But I added window.__game — the inspect action may not return JS values. Let me add console logging to verify movement: e.g., log player x when crossing certain thresholds? Simpler: temporarily log player x every second? That pollutes console. Alternative: in the inspect output I only get console logs and DOM text. I can make the game draw current player x / state into a hidden DOM element that the inspect's DOM dump includes. E.g., a hidden div with id "debug" whose textContent updates each frame with state info: state, score, lives, playerX, aliensLeft, bunker cell counts. The DOM dump in inspect shows text of the page — it showed only visible text? It showed "PROCEDURAL INVADERS\nRESTART\n..." so it includes text content. If I add an aria-hidden offscreen div, it may include it. Let me add a visually-hidden (but present) element updated each frame. That's a robust inspection channel. I could keep it in the final file harmlessly, or remove it later. I'll add it as a hidden status div (display:none might be excluded from DOM dump text; use a clip technique: position absolute, 1px). Let's try.

Plan for testing:
1. Add hidden debug div updated each frame with JSON of key state.
2. Reload, inspect: initial formation, bunkers cell counts, lives 3, score 0.
3. Send ArrowRight key repeatedly, inspect debug div for playerX increase.
4. Send Space, check shots count increases, then after a bit check score or bunker damage.
5. Aim player under a bunker and fire several shots to erode bunker: compare bunker cell counts before/after.
6. Check alien kill → score increase.
7. Click RESTART → verify lives=3, score=0, bunkers full, aliens back to 50, player centered.

Let me first make the small HUD fix (lives icons = lives) and add the debug div.

Wait — `dbg` is defined inside the IIFE and setInterval uses `state`, `player`, etc. — those are in scope. Good. But `dbg` const declared before `window.__game` — fine.

Reload and inspect.

The debug readout works, but "aliens=" printed the array. Fix: use aliveAliens().length. Let me fix that in the setInterval.

Also I notice the player cannon at x=430 (centered, W/2 - 20 = 430). Good. Bunkers full at 186 cells each.

Fix debug line, then test movement: send ArrowRight key. Question: does the key action hold the key or press+release? Let me test with a key action and then inspect after a delay.

Actually to test sustained movement, I might need to send many keys. Let me first fix the debug and then test.

Now test movement. Send an ArrowRight key and inspect after ~1s. The browser `key` action — let me try with text "ArrowRight". First reload, then send several key presses in sequence and inspect.

Now test movement: press ArrowRight key. The browser tool `key` action takes text. Let me send key "ArrowRight" and see if player x changes.

Interesting: alien formation moved right (as expected — it started moving right), an alien shot is descending toward the player, and the middle bunker has visible damage (186 → 180 cells) — the alien shot eroded bunker material from below (top-right corner of middle bunker shows a notch). 

But the player x didn't change (px=430 still). The key action may deliver a keydown+keyup quickly; the player should move a tiny amount during that frame... Actually the keydown happened, then keyup — between them possibly no animation frame elapsed, so no movement. I need sustained key hold. Options: dispatch keydown repeatedly via... I can't run arbitrary JS. 

Hmm. Maybe the `key` action supports holding? Let me try pressing 'd' several times in quick succession — each press/ release may still fall between frames. Alternatively use click/drag? Another approach: use `type` action? No.

Better: the harness `key` action likely supports repeat. Let me just try sending multiple ArrowRight keys in a row (several tool calls) and see whether px increases at all. Actually a smarter approach: my game could also support touch/click controls — but the test requirement is keyboard.

Alternative approach to verify movement robustly: send many rapid key events. Each keydown sets keys[k]=true; keyup sets false. If the harness sends keydown+keyup immediately (same tick), movement never registers since update runs on rAF. That's a real risk in a headless environment, but in a real browser a human holds the key. Still, to be resilient (and testable), I could add a small "input buffer": on keydown for a movement key, apply an immediate impulse (e.g., move player by ~18px instantly). Hmm, that would feel odd for real players? A small nudge on keydown is barely noticeable, and holding still gives smooth continuous movement. Actually better: track keydown timestamps and in update, if key was pressed within last 100ms treat as held even if keyup came... no, simpler: on keydown of movement key, immediately shift the player by 10px (clamped). This guarantees discrete presses move the cannon, and continuous holding moves smoothly. This is a legit responsiveness improvement (instant response on key press).

Let me implement: in keydown handler for ArrowLeft/a → player.x -= 14 (clamped), ArrowRight/d → += 14. But player might be null before reset — resetGame runs at load, fine.

Also for Space: fire on keydown immediately? Fire cooldown bounds rate; on keydown we can attempt an immediate shot spawn (same as holding). That makes discrete taps fire, which is good UX anyway. I'll refactor shooting into a `tryFire()` function called from both keydown and update loop.

Let me implement that. Then test: press ArrowRight a few times, check px increases; press Space, check pshots or score.

Also the bunker already shows damage from alien fire — good, that verifies "hits from either side remove bunker material persistently".

Let me refactor.

Wait — tryFire is called from update loop only when fireTimer <= 0, but tryFire itself checks fireTimer > 0. Fine.

Reload and test: tap ArrowRight a few times, tap space, check state.

Now test movement taps and firing. Send key ArrowRight, then inspect.

Movement works: px went from 430 → 451 (15px nudge + ~6px from a held frame or two). Bunkers are eroding from alien fire (170, 182), formation descended to fy=118 after hitting the left edge and reversing — it moved right then hit the right edge? Formation started x=220, width 480 → right edge 700; PLAY.right=882. Hmm, it reversed already? fy=118 = 92+26, so one descend happened. In the screenshot the formation is on the left side moving left, having reversed at the right edge. Right edge reached 882 → reversed and descended. Good.

Also visible: bunkers show notches from alien fire.

Now test firing: press Space. The player is under a bunker at x=451... the middle bunker spans x≈405-495. The shot will hit the bunker. That's good for testing bunker damage from above. Let's fire several times and check middle bunker cell count decreases, and check that a shot passes through gaps later.

Press space a few times.

Firing works: a player shot is visible above the cannon heading up into the middle bunker, and an enemy shot is descending near the player. The middle bunker shows big erosion (161 cells). The player shot will chew the middle bunker from below... Actually the shot is at y just above player and the bunker above it — the player shot should hit bunker material soon. Bunker middle: 161 cells already (from alien fire + maybe a player shot earlier).

Now: I need to verify a shot kills an alien and score increases. Player is at x=451 under the middle bunker; the bunker is heavily damaged. Let me fire repeatedly (multiple space presses) and check score increases. Note rate limit 0.26s; taps should mostly succeed.

Let me fire several times.

The middle bunker now has a clear channel burned through from below (visible vertical gap the shot is passing through) — this verifies "shots can subsequently pass through the resulting gaps". The formation descended to fy=170 and is now at the left, moving left/reversing.

Now fire more to get through the gap and hit an alien. The player is at x=451; the gap in the middle bunker is around x≈620 screen → canvas x ≈ 620-152 = 468... roughly aligned with the player. Fire several times.

Aliens have descended to fy=222 and are approaching. The player shot will reach them in a moment. Let me fire a few more times and check console for "alien killed" log and score increase. The alien bottom row is at y = 222 + 4*34 = 358 to 382. Shot at 470px/s from y≈566 takes ~0.4s. Fire again.

Aliens are descending fast toward the player. They'll likely reach the zone before my shots kill any (my shots are eaten by the bunker gap alignment). The player shot is passing through the middle bunker gap. But the aliens are at fy=274 and descending26 per reversal; they reverse often because the swarm is wide (480px) and they're now spanning... They will probably hit the zone and end the game before I can kill one. That's fine — it tests the "aliens reaching the player zone → Game Over" path. But I still need to verify an alien kill + score.

Rather than relying on aim, once the game ends I can restart and let aliens come close, then fire — kills should be easy when aliens are near. Or better: after restart, immediately move to a position and spam fire.

Actually the game may end soon. Let me wait and check state=over, then verify the Game Over overlay renders, then press Space to restart and verify reset values (lives=3, score=0, bunkers full, aliens=50, px=430).

Aliens are grinding into the bunkers (they're overlapping the left bunker and eating it away — visible). They're at fy=326, bottom row at ~484, zone kill at 536. A few more reversals and game over. Fire now while aliens are just above the bunker — the shot will hit them.

The console logged "[game] alien killed (octo, row 4) +10 -> score=10, aliens left=49" — alien kill and score increment verified. (The debug snapshot was taken just before that frame, hence showing score=0, aliens=50.)

Now let the game reach Game Over (aliens descending into the player zone), verify overlay, then restart. Aliens at fy=352, bottom row bottom = 352+5*34=522... wait zone kill at 536, bottom row y = 352 + 4*34 = 488, +24 height = 512. Close. Another descend → 378 →538 ≥ 536 → game over. Let me wait.

Game Over works and the overlay renders. Bug spotted: the "GAME OVER" console log fires repeatedly every frame — because the zone check runs per alien inside the loop, and once state is 'over' the loop continues (state check happens at top but the alien loop doesn't break). Actually the whole alien-motion block is inside `if (state === 'playing')`, but within the per-alien loop, once state is set to 'over', the loop keeps iterating and sets state='over' again for every subsequent alien that also crosses the line, logging repeatedly. Fix: break out of the loop when state changes.

Fix in the alien loop:
```js
if (formation.y + (a.row + 1) * ALIEN.ch >= ZONE_KILL_Y) {
  state = 'over';
  ...
  break;
}
```
Add break.

Also the overlay text overlaps the aliens visually (fine, it's semi-transparent panel).

Now restart and verify reset. Then also verify win state and life loss? Let me also test:
- Restart via button click → verify formation, bunkers full, lives=3, score=0, px=430.
- Life loss via enemy shot: hard to force deterministically, but I can verify it happens over time by leaving game running without firing until lives decrease. With 3 lives it might take a while. Alternatively I trust the code path but verify at least one life loss occurs by idling. Let me do the restart test first, then idle a while and watch lives drop (aliens fire increasingly often as they descend; player is stationary at center under a bunker, so shots may hit the bunker... the player at px=430-470 is under the middle bunker which blocks many shots. Hmm, but alien erodes bunkers over time, and shots will get through.)

Actually a better test: move the player out from under bunkers (to the far left/right gap) and idle. Let me press ArrowLeft several times to move to x≈20, then idle and watch lives.

Also I want to verify win state. I could... playing through 50 aliens by tapping space is impractical. I could trust the code (state='win' when alive.length===0). It's simple code. Alternatively verify via a quick hack: no evaluate access. I'll skip full win verification but the logic is straightforward and mirrors the verified game-over path. Actually, I could partially verify by... no easy way. Skip; note as unverified.

Let me first fix the repeated log bug, reload, then test restart + life loss.

Also: the repeated GAME OVER logging spam happens per frame? No — only once per alien crossing per frame, but it kept logging over6 seconds of screenshots... Each inspect shows accumulated console. It logged 9 times, likely all in the same frame(s) as several aliens crossed. But possibly every frame — no: after state='over', the `if (state === 'playing')` block is skipped entirely, so it only logs once per alien that crosses in that final frame. Wait, but the log appeared ~9 times, matching ~9 aliens in the last row crossing simultaneously. Right. Still, fix with break + guard.

Also, I should double check: when state==='over', player shots can't fire (tryFire checks state==='playing'), alien shots stop updating? They still update (loop outside state check) but loseLife only triggers when state==='playing' — fine.

Let me make the fix.

Now reload and test restart via button click, then verify reset state.

Clean initial formation again. Now let the game play a bit, get some damage/score, then click RESTART and verify restoration. To make the restart test meaningful, first play a little: move left a few taps and fire, then click RESTART and verify all restored.

Let me move player left several times (to expose to enemy fire too) and fire a few shots.

Left movement works (px 430 → 409; the -15 nudge plus a held frame). Now let's get hit a few times to test lives. The player at x=409 is under the middle bunker (which spans 405-495)... player spans 409-449, partially under bunker left edge. Let me move further left to x≈200 (between left bunker at 180-270 and middle at 405-495 — gap around 270-405). Press ArrowLeft ~8 times → 409 - 8*15 = 289. Hmm still near bunker edge. Let me press12 times → 229? That's under the left bunker (180-270). I want a gap: between 270 and 405 → x around 310-360. Press ArrowLeft 5 times: 409-75 = 334. Good, that's in the gap between left and middle bunkers.

Then idle and wait for enemy shots to hit. Aliens fire rate ~0.3-1.5s intervals. Player invuln 2.2s after each hit. Might take ~20-40s to lose 3 lives. Let's do it.

Actually let me first click RESTART to verify restoration, then do the lives test (final state doesn't matter).

Restart via button works: formation50 aliens at fy=92, bunkers 186/186/186, lives=3, score=0, px=430 centered, WAVE 1 banner. 

Now test the lives mechanic: move the player into a gap between bunkers and idle until hit. Player at 430 → move left 5 taps → 334 (gap between left bunker ending ~270 and middle starting ~405). Actually player width 40, at x=334 spans 334-374 — that's in the gap. Good.

Then idle ~40s and watch lives decrease. Meanwhile check invulnerability behavior (lives shouldn't drop twice within 2.2s).

Let me send 5 left taps. Each browser key action is one tap. I can do them sequentially.

Hmm, the formation is at fy=170 already — the game has been running while I slept. The aliens are descending quickly and the game may end before I lose 3 lives. Note that the click test waited3s; the game continued.

I need to move into the gap and wait. Let me send 4 more left taps quickly.

Life lost: "player hit -> lives=2" — lives decremented to 2, and the HUD shows 2 life icons. Player respawned at center (px=415 — mid-respawn nudge from my ArrowLeft tap). An enemy shot is visible right next to the player. Invulnerability should protect it.

Now let me wait for further hits → game over on zero lives. Meanwhile verify no double-hits within invuln. Let me idle ~20s and check.

Game over happened via alien descent again (the swarm descends fast once thinned? No — it's 50 aliens, but descent every reversal, and they reverse often since the swarm is 480 wide with 864 playfield... they reverse at the edges. Starting y=92, descend 26 per reversal; ~11 reversals → game over; each traverse ~800px at ~26-40px/s ≈ 25s... but we saw game over in ~25s total. Hmm, that means reversals happened faster than expected. Wait — speed: 26 + (1-ratio)*118 + elapsed*0.35. With 50/50 alive, ratio=1, so speed=26 + elapsed*0.35 capped at 22. So ~26-48 px/s. Traverse of ~380px (they only reverse when hitting edge, formation starts centered with 200px margins each side) → ~10-15s per traverse. 11 reversals → ~2 minutes. But we saw game over ~30s after restart. Hmm.

Oh wait — the game was running during my sleeps: total elapsed from restart click to game over ≈ 3 + (taps) + 20 = ~25-30s. That's too fast for 11 reversals at 26px/s. Let me check: is something making the formation descend repeatedly? Look at the earlier sequence: after restart at fy=92, then fy=170 (after ~4s?), fy=352, fy=378. Between first screenshot after restart (fy=118) and later (fy=352) — that's 9 descents. Something's causing rapid reversals — possibly the playfield edges: PLAY.left=18, PLAY.right=882 — formation width 480 spans... The check uses leftEdge/rightEdge of alive aliens only. Hmm, but reversal also triggers if `rightEdge + step > PLAY.right` — fine.

Wait, look at the screenshot at fy=352: the formation is at the left, x≈255 (screen) → canvas ~103. And they had descended a lot. Actually, notice the aliens in that screenshot are NOT all alive? They are — 50 aliens.

Hmm, let me reconsider: reversals happen when the formation hits the left or right wall. But there's another possibility: the speed formula includes `(1 - ratio) * 118` where ratio = alive/total. With 50 alive ratio=1 → 0. OK.

So why did it descend 9 times in ~15s? Because traverses are short: from centered start x=212 (formation.x = (900-480)/2 = 210), leftEdge=210, rightEdge=690. To hit PLAY.right=882 the formation must move 192px at26px/s = 7.4s. Then to left edge: from 690-192=498... wait leftEdge must reach PLAY.left=18: leftEdge starts210, after first reversal at x=402... it takes (402-18)/26 = 15s. So the first two descents take ~22s. But we observed fy going 92→118→144→170→222→274→326→352→378 quickly.

Ah — I bet the issue: my key actions and clicks happened with delays; each browser tool call takes ~5-10s wall time. Between the restart click and the last check, wall time was ~30-40s, but the game time elapsed matches roughly: 9 descents in ~35s means ~4s per traverse, which implies speed much higher than 26px/s.

Hold on — is `elapsed * 0.35` capped by `Math.min(elapsed * 0.35, 22)`? Yes, capped at 22. So max speed ~48px/s at start. Traverse192px → 4s at 48px/s. Then next traverse is 846-... let me compute: after first reversal at right edge, formation moves left until leftEdge = 18: distance = 402-18 = 384px → 8s at 48. Then right again846-... leftEdge=18 → rightEdge=498, need rightEdge→882: 384px → 8s. So descents every ~8-12s after the first. In 35s: about 4 descents → fy≈ 92+4*26 = 196. But we saw fy=378 = 92 + 11*26.

So the formation descends faster than my model. Something's off. Possibly multiple descents per frame? Look at the reversal code: when `formation.dir > 0 && rightEdge + step > PLAY.right` → set dir=-1, descend. But next frame, dir=-1 and leftEdge - step < PLAY.left? No.

Unless... `alive` aliens: after an alien dies, minCol/maxCol change, but 50 aliens alive.

Wait — maybe the issue is the shot from my taps... no.

Let me re-read the descend logic. It's inside the `if (state === 'playing')` block, executed once per update. Hmm.

Actually! Look again at the screenshots. In the fy=352 screenshot, the formation x span was ~103..583 (canvas). In the fy=378 (game over) screenshot, formation at canvas x≈440..920-... The screenshots show formation left at ~103 canvas. OK.

Let me just measure: I'll add formation x/dir to the debug readout and watch over a few seconds. Actually simpler: the wall-clock discrepancy may just be that each of my tool calls takes a long time (the harness said frame delays). Between reload (restart #2) and the "player hit" check, I slept 3s + tool latency. Between that and the 20s sleep, more latency. Total maybe 40-60s of game time. At 4 descents/35s estimate that's fy≈224, but we saw 378. Still a mismatch.

Hmm, let me look for a bug: `if (formation.dir > 0 && rightEdge + step > PLAY.right)`. `step = speed * dt`. If dt is large... capped at 0.05. step max = 48*0.05=2.4px. Fine.

OH WAIT. I see it. The alien-erosion loop breaks out with `break` when the zone is reached... that's fine. But look: the reversal check uses `alive` computed at the top of update — fine.

Hmm, what about `formation.y += ALIEN.descend` — 26 per reversal. 11 reversals needed for fy=378. In ~45s that's a reversal every 4s. At 26-48px/s that requires traverse distances of ~100-190px, i.e., the formation bouncing within a short horizontal span. Could the aliens be reversing at "PLAY.left"/"PLAY.right" —18/882 — no...

Unless minCol/maxCol: `for (const a of alive)` — alive is filtered array of alien objects with col property. Right.

Hmm, but actually maybe the game was running longer than I think: reload → I did key ArrowLeft, click RESTART (with 3s sleep + latency), key ArrowLeft, key ArrowLeft ("player hit"), then20s sleep. Total wall time maybe 60-90s given harness latency. At 45-60s game time, ~11 reversals means a reversal every ~5s, traverse ~150-250px at 30-48px/s → plausible if the playfield is narrower than I think... 

Let me just measure directly: add fx (formation x) and fdir to debug, reload, and watch for10 seconds to count descents. This matters for game feel: if the swarm descends too fast, games are short (~40s), which is too punishing. Classic Space Invaders takes a while. I might reduce descend frequency by making the swarm faster horizontally (so traverses are quick but descents rare — actually classic SI speeds up; the descent per reversal is the difficulty driver).

Actually classic SI: aliens move in discrete steps synchronized with their "theme" music; a full traverse takes ~4-8s and they descend 8px per traverse, reaching the bottom in ~50-60 descents. My descend of 26px needs only21 descents... wait, 640-92-... from y=92 to536 = 444px / 26 = 17 descents. Too few. With traverses every ~8-12s, game lasts ~2-3 minutes. Hmm, that's if my math holds.

But observed: 11 descents in ≤45s. So traverses were ~4s each. Speed would need to be ~100px/s. Is the speed cap applied? `const speed = 26 + (1 - ratio) * 118 + Math.min(elapsed * 0.35, 22);` — elapsed *0.35, capped 22. With 50 aliens, speed = 26+0+something ≤48. Traverse 384px at 48 = 8s.

Unless... dt! `Math.min((now - last)/1000, 0.05)`. If the browser tab is backgrounded/throttled, rAF may pause and dt clamps to 0.05 — that would slow the game, not speed it.

Wait — maybe I misread and there were more elapsed seconds. Let me count tool calls: after clicking RESTART I did: key ArrowLeft (fy=170!), key ArrowLeft (fy=352), then 20s sleep → fy=378 game over. 

The very first key after restart already showed fy=170 — that's 3 descents right after a restart! The restart happened at the click (frame showed fy=92 formation intact). Then one tool call later (a few seconds) → fy=170. That's 3 descents in a few seconds. So the formation IS bouncing rapidly.

Why? Look at the screenshot at fy=170 (after first ArrowLeft post-restart): the formation spans canvas x≈255..730 — that's 475 wide, centered-ish. Fine.

Hmm! I bet the bug: `formation.dir` flips, descend happens; then next frame dir=-1, but check `leftEdge - step < PLAY.left`... leftEdge is large, false. OK.

OH. I see it now! In the alien-erosion loop I added `break` — but there's another `break`... no.

Let me look at the actual current code again to be sure of what's there.

Actually, wait. Maybe the issue is `PLAY.right` vs formation: the reversal condition `rightEdge + step > PLAY.right` triggers when the right edge is within one step of the wall. Since the formation is smooth-moving, it reverses once and moves away. Fine.

Alternatively — multiple reversals per frame can't happen.

Hmm, is it possible that `formation.y` isn't the only descend source... `banner`... no.

Let me just instrument: add fx/dir to debug and observe over ~15s.

Actually — hold on. I wonder whether the *click* on the RESTART button also triggered a keydown? No.

Another thought: `nudgePlayer` — irrelevant.

Let me look at the real possibility that dt is huge on the first frame after reload: `last = performance.now()` set at script eval; first frame dt small. Fine.

Just instrument and measure. Let me add fx and fdir to the debug line.

I need to wrap up. Let me quickly reload, measure formation motion over a few seconds, and if the swarm descends too fast (making the game unwinnable/too short), tune the descend/speed. Then final check and done.

Initial: fx=213, dir=1, fy=92. Let me wait ~10s and check how far it moved and whether it reversed/descended.

Given time constraints, I'll do one 10s observation, and if descent rate is too high, tune: increase horizontal speed a bit and reduce descend to ~20px, and start the swarm higher... Actually the key metric: traverse. Let me measure.

Game time t=27.5s after ~12s wall (background throttling makes game time run differently — actually t=27.5 means the game clock advanced 27.5s; the tab may run faster or my sleeps plus latency). fx=289, dir=1, fy=144 → 2 descents in 27.5s. That's reasonable: traverse ~13s each. So my earlier confusion was tool-call latency (each call takes ~10s wall; the game had run longer than I assumed). At 2 descents/27s, ~17 descents to reach the bottom ≈ 4 minutes minimum — good pacing, and it accelerates as aliens die.

So the pacing is fine. Earlier "fy=378 game over" happened because lots of wall time had passed across my sequential tool calls (each with sleeps) — total ~90s+. Fine.

Everything essential is verified:
- Movement left/right ✓ (px changes)
- Fire ✓, fire rate bound (cooldown), shot lifetime bound ✓ (code)
- Alien formation motion, edge reverse + descend ✓ (fy increased, fx direction changes)
- Alien fire toward player ✓ (aimed bolts, eroding bunkers)
- Bunker damage from both sides ✓ (cell counts decrease; visible notches/gaps; shots pass through gaps seen)
- Alien kill + score once ✓ (console: +10 → score=10, aliens=49)
- Lives decrement on hit ✓ (lives=3→2, HUD), invulnerability code (2.2s) — partially verified (no double-hit observed)
- Game Over via zone ✓ and zero lives (code path, same as verified)
- Restart restores ✓ (aliens 50, bunkers 186/186/186, lives 3, score 0, px 430)
- Controls displayed ✓ (on canvas HUD + bar)
- Cannon clamped in playfield ✓ (code clamp; movement stayed within)

Remaining unverified: win state (needs clearing 50 aliens), zero-lives game over directly. Both are simple, mirrored code paths.

One last thing: remove the debug instrumentation? It's harmless (hidden div, offscreen). Keep it — useful, invisible. Actually let me keep the file as is; it works.

Time is short — finalize. File is saved. Let me do a final quick syntax sanity check with node (parse the script?) — not trivial. The game runs fine in the browser, so it's fine.

Final quick check: one more fire/move tap to confirm nothing broken after last edit (debug line edit). Already reloaded and running fine (fx moving, aliens firing). Good.

Report.