A doodler character jumps upward through a vertical grid of platforms, with controls for left, right, and upward movement. The game tracks a score, detects collisions with platforms to trigger jumps, and ends when the doodler falls below the bottom. Rendered as an HTML/CSS animation in a 400-by-500 grid, it updates state every 50 milliseconds via `setInterval`, with keyboard input handled through a `keydown` event listener. Platforms reset when they scroll past the bottom, and the game-over screen displays the final score.