Snake Game

🐍 A browser-based Snake game built with vanilla HTML, CSS, and JavaScript. No frameworks, no build tools, no network requests — just open and play.

👉 Play the Live Demo here

How to Play

1. Open index.html in any modern browser (Chrome, Firefox, Safari, Edge)
2. Click Start Game or press Enter
3. Control the snake with Arrow Keys or WASD
4. Collect food to grow and increase your score
5. Avoid walls and your own tail
6. Your highest score is automatically saved locally, so you can try to beat it next time you play!

Controls

Action	Keys
Move	Arrow Keys / WASD
Pause	Escape / P
Resume	Escape / P / Resume button
Start / Restart	Enter / Button click

Features

• 20×20 grid with smooth movement
• Speed progression (10 levels) as you score
• High score persisted across sessions via localStorage
• Pause/resume with overlay
• Auto-pause on window blur
• Responsive layout (320px–1920px)
• Dark theme with accessible contrast ratios
• Win condition when the board is completely filled

Project Structure

├── index.html       # Game UI with three screens
├── style.css        # All styling and responsive layout
├── game.js          # Game logic, controller, and rendering
├── package.json     # Dev dependencies (fast-check for tests)
└── tests/           # Property-based and unit tests

Running Tests

To install dependencies and run the test suite, execute the following commands in the project root:

npm install
npm test

Tests use the Node.js built-in test runner and fast-check for property-based testing. All 68 tests validate 12 correctness properties covering movement, collisions, scoring, input handling, and persistence.

License

This project is licensed under the MIT License.