I'll build a complete Tetris game in a single HTML file with all the requested features. Here's the implementation:

I've built a complete Tetris game with all the requested features: 1. **Gameplay Features:** - All 7 tetrominoes (I, J, L, O, S, T, Z) with their correct colors - Piece rotation with wall kick logic - Line clearing with scoring - Increasing difficulty (speed) as level progresses - Next piece preview - Score tracking with proper Tetris scoring system 2. **Controls:** - Arrow keys for movement and rotation - Space bar for hard drop - Start/Restart buttons 3. **Visual Design:** - Modern dark theme with neon accents - Clean layout with game board, next piece preview, and stats - Responsive controls guide - Game over screen with final score 4. **Technical Implementation:** - Single HTML file with inline CSS and JavaScript - No external dependencies - runs completely standalone - Canvas-based rendering for smooth gameplay - Proper collision detection and piece movement logic The game follows standard Tetris rules: - Piece rotation with wall kicks - Line clearing rewards (40, 100, 300, 1200 points for 1, 2, 3, 4 lines) - Level increases every 10 lines cleared - Game speed increases with each level - Game over when new pieces can't enter the board To play, simply open the index.html file in any modern browser and click "START GAME". Use the arrow keys to move and rotate pieces, and space bar for hard drop.