How to play Vertical Jump
| Keys | Action |
|---|---|
| ← → | Steer |
| A D | Steer |
| Drag | Steer |
| P | Pause |
| R | Restart |
| M | Mute |
On phones and tablets, use the on-screen tactile D-pad under the viewport.
About Vertical Jump
Vertical Jump is an endless climbing game. Your character bounces automatically every time it lands on a platform, and you only steer left and right. Platforms only catch you on the way down. The side walls wrap around: leave the left edge and you come back on the right. The run ends when you fall off the bottom of the screen.
Scoring, levels and tips
- Your score is your peak height, one point per 10 units. A normal bounce rises about 168 units, roughly 16 points.
- Springs, marked with a zigzag, launch you about three times as high as a normal bounce.
- Moving platforms, marked with slots, slide side to side. Crumbling platforms, drawn with a dashed outline, give one bounce and then fall away.
- Below a height of 220 you only meet normal platforms and springs. After that, moving platforms grow from 10% to 30% of new platforms and crumbling ones from 8% to 22%, and the largest gap widens from 96 to 132 units.
- Your best height and number of runs are saved in your browser, and a dashed line marks your record.
- Tip: the bounce is automatic, so line up over the next platform on the way down, not on the way up.
- Tip: near one edge, a platform by the other edge is often quicker to reach through the wall.
- Tip: a crumbling platform is gone once used, so don't plan to come back to it.
How it's built
The game is written from scratch in TypeScript on an HTML canvas, with no game framework. The platform generator keeps every run fair. For each new platform it picks a vertical gap well below the height of a normal jump, solves the jump equation for how long the player takes to rise that far, and allows only as much sideways offset as the player can cover in that time, with a safety margin and a hard cap.
Landing uses a swept test: it checks whether the player's feet crossed a platform's top during the step and takes the highest one, so a fast fall can't pass through a platform. The simulation uses a seeded random number generator and runs at a fixed 120 updates per second, and sound comes from the Web Audio API. You can steer by keyboard, on-screen buttons, dragging, or tilting your phone where the browser allows it.