The brief
Create a single-file HTML/Canvas platformer. The player should be able to run, jump, collect coins, and reach a goal flag. Include a reset button and a simple parallax background. No external assets beyond a small amount of CSS.
The prompt leaves room for interpretation: camera behaviour, level layout, physics constants, and visual styling are all up to the model. The best outputs fill those gaps with sensible defaults rather than leaving them undefined.
What a strong output looks like
- Solid, one-way platforms that the player can jump up through but land on.
- A compact level with clear visual affordances for hazards, coins, and the goal.
- Restart that fully resets game state: coins reappear, the timer resets, and the player spawns at the start.
- Parallax background tied to camera movement rather than raw player position.
- Controls feel responsive: arrow keys or WASD, plus space to jump.
Scoring notes
- 40% playability: a human can complete the level without unfair deaths or stuck states.
- 30% collision correctness — no falling through floors, no wall-clipping, no phantom ground contacts.
- 20% completeness — coins, goal, reset, and a parallax background are all present and working.
- 10% polish — particles, squash-and-stretch, coyote time, or sound effects.