Build a complete 2D platformer game in a SINGLE self-contain...

Prompt

Build a complete 2D platformer game in a SINGLE self-contained HTML file. No external libraries, images, fonts, or sound files: everything must be drawn with <canvas> and synthesized with the Web Audio API. It must run offline by opening the file. CORE MOVEMENT (must feel tight, like Celeste-lite) - Run with acceleration/deceleration (not instant velocity). - Variable-height jump: releasing the jump key early cuts the jump short. - Coyote time (~100 ms) and jump buffering (~100 ms). - Wall slide and wall jump. - Physics must run on a fixed 60 Hz timestep, decoupled from rendering, so the game plays at identical speed on 60 Hz and 144 Hz monitors. PROCEDURAL LEVELS - Levels are generated from a numeric seed using your own seeded PRNG (not Math.random). The seed is shown on screen; pressing R regenerates the same level from the same seed. - EVERY generated level must be guaranteed completable. The generator must verify reachability from spawn to exit using the player's ACTUAL jump/movement parameters, and regenerate if verification fails. - Press G to toggle a debug overlay that draws the path your verifier found. - Difficulty increases each level (longer gaps, more enemies, fewer safe platforms). - Press N to skip to the next level (for testing). ENEMIES (2 types with distinct AI) - Ground patroller that turns around at ledges and walls (never walks off edges). - Flying enemy that chases the player only when it has line of sight (blocked by solid tiles), and drifts back to its home position otherwise. - Stomping an enemy kills it and bounces the player; side contact kills the player. GAME SYSTEMS - Collectible coins, a HUD (level, coins, deaths, timer), a pause menu (Esc), a title screen, and a death -> instant respawn loop. - Best time per level saved in localStorage, wrapped in try/catch so the game still works if storage is blocked. GAME FEEL - Screen shake, particles on landing/jumping/death, squash-and-stretch on the player, and a camera that smoothly follows with look-ahead in the movement direction. - Synthesized sound effects for jump, land, coin, stomp, and death. Controls: Arrow keys/WASD to move, Space/Z to jump. Show controls on the title screen. Output only the complete HTML file. Before the code, write at most 5 sentences explaining how your reachability verifier works.

A system prompt was added to support web rendering