Rerun is built on one idea: when you die or restart, your previous attempt replays alongside you as a ghost. Every level is designed so that you can't finish alone — you need your past self to hold a switch, block a hazard, or give you a platform to stand on.
That turns each level into a planning problem rather than a reflex test. You aren't trying to play perfectly; you're trying to play *usefully*, so that the version of you that comes next can finish the job. It's a genuinely original mechanic and the levels are short enough to keep experimenting.
Each attempt is recorded. When you restart, that recording plays back as a ghost that does exactly what you did, at the same times — so you can use your past self as a switch-presser or a platform.
It's a thinking game rather than a reflex one. The platforming is forgiving; the difficulty is working out what your earlier selves need to have done.
Yes — it runs in the browser with nothing to install.