Shadow Tap
Rooftop parkour measured in milliseconds.
A reflex runner with deterministic levels, frame-accurate input, and a replay file small enough to share in a message.
- Released
- January 2025
- Installs
- 420k installs
- Store rating
- 4.7 ★ / 6.9k ratings
- Built with
- Unity · C# · deterministic replay
The build
Shadow Tap is built for players who want to beat a time, not survive a random seed. Every level is fixed and deterministic, so the same inputs always produce the same run — which means a completed run can be stored as a 4KB input trace instead of a video.
Those traces power the ghost system: the leaderboard hands you the input trace of the run one place above yours, and your rival is replayed beside you in real time. It cost almost nothing in bandwidth and became the reason people stayed.
Input latency was the whole project. We poll touch events off the render thread and kept end-to-end response under 50ms on mid-range Android, verified with a high-frame-rate camera rather than a profiler.
What shipped
- Deterministic levels stored as 4KB input traces
- Ghost races against the run one place above you
- Sub-50ms touch-to-render latency on mid-range Android
- 68 levels across four rooftop districts
