### Purpose
Build a simple 2D platformer endless runner game that runs in the browser.

### Game Design

**Visual Style**
- Minimalist geometric aesthetic
- Player is a colored square/block
- Platforms are simple rectangles
- Clean background with parallax scrolling layers
- Subtle particle effects on jump and landing

**Player Character**
- Simple square shape with a face or eyes for personality
- Smooth jump arc with gravity
- Can jump while on ground only (no double jump)
- Squash and stretch animation on jump/land
- Death animation: block shatters into pieces

**World & Obstacles**
- Auto-scrolling from right to left
- Platforms at varying heights
- Gaps between platforms (must jump over)
- Spike obstacles on platforms (instant death)
- Moving platforms (up/down or left/right)
- Low ceiling sections (timing required)

**Difficulty Progression**
- Speed gradually increases over time
- Gaps get wider
- More obstacles appear
- Moving platforms move faster
- Difficulty resets on death

**Scoring**
- Score increases with distance traveled
- Bonus points for close calls (near-miss spikes)
- High score saved to localStorage
- Current score and high score displayed

**Game Flow**
- Start screen with game title and "PRESS TO START"
- Tap/click anywhere or press button to begin
- Game starts immediately after input
- Death shows "GAME OVER" with final score
- "TAP TO RETRY" or press button to restart

### Controls

**Keyboard**
- Space: Jump
- Up Arrow: Jump
- Enter: Start game / Restart

**Gamepad Support (IMPORTANT)**
The entire game must be playable with a gamepad controller, including menus:
- Use the Gamepad API: https://developer.mozilla.org/en-US/docs/Web/API/Gamepad_API
- A button (buttons[0]): Jump
- A button on start screen: Begin game
- A button on game over: Restart game
- Start button (buttons[9]): Pause game
- Show "Gamepad Connected" message when controller detected
- Poll gamepad state in game loop using `navigator.getGamepads()`

**Touch Support**
- Tap anywhere on screen to jump
- Works on mobile devices

### Technical Notes
- Use HTML5 Canvas for rendering
- 60 FPS game loop with requestAnimationFrame
- Simple physics: gravity constant, jump velocity
- Procedurally generate platforms ahead of player
- Remove off-screen platforms for performance
- Responsive canvas that scales to fit screen
- No external dependencies needed