Glowfall

You descend a lightless cavern carrying a lantern, and the rule is simple enough to read in one jump: terrain only exists where light falls on it. Unlit rock is invisible and you drop straight through it. The pool around your lantern is the floor, and it moves when you do.

So the only way to reach ground you cannot already stand on is to throw the light at it — and for the second and a half the lantern is in the air, it is lighting the gap between two ledges rather than either of them. The ledge you left goes dark under your feet. That is the game.

How it plays

• Five caverns, each generated from a fixed seed, each guaranteed traversable by construction: the route is built out of steps that the real jump arc can actually make, never out of an estimate of it.
• A 0.12 second grace before darkened ground stops holding you, drawn as a fade, so losing the floor is something you can see coming rather than something that happens to you.
• Light-motes widen the lantern. A bigger pool is a safer descent and a duller one — the reward and the difficulty dial are the same number, and dying costs you one.
• Coyote time and an input buffer, because the whole game is precision jumping in the dark and it has to be fair rather than exact.
• Recall the lantern instantly and it arcs back to your hand. Sometimes that is the panic button.

Three colours and light. Everything you can see is a silhouette, a lantern, or a mote; everything else is what you cannot see yet.