You climb a tower that has no top.
Two things want you dead, and they want opposite things. A wall of fire rises from below, so you can't stop moving. But every move burns oxygen, and the air only gets thinner the higher you go, so you can't just sprint either. The whole game lives in the narrow band between too slow and too fast.
One thumb runs all of it. Tap left, tap right, and you climb. Grab oxygen tanks as you pass them. They ride on your back as cargo. Bleed one to breathe, or carry a full load to an airlock and sell it for credits. Hoarding pays more. It also kills more.
Higher up, the tower stops being polite:
- Meteor showers you hold through and wait out.
- Dust clouds roll across Elysia and take your sight. Everything goes black except the circle under your lamp.
- The air thins until one wasted second is the whole difference.
Spend what you earn down in the shop. A reserve tank for the moment your lungs hit zero. A thruster to leap past a bad stretch. Plating that eats one hit before it burns off. Or buy a camp and start your next run partway up, past the ground you already know cold.
You don't climb alone. Your best run climbs beside you as a ghost. Tap a name on the leaderboard and race that one instead, their real run, chop for chop. And the dead are up here too. Every climber who fell left a body drifting in the dark with the cargo still on their back. Reach one and it's yours.
There is no summit. Nothing to unlock at the top, no credits to roll. There is only how high you got, the wall that finally caught you, and the next run.
Buy air. Sell air. Don't run out of air.