Inversion

Inversion is a puzzle platformer set in the same hollow world as Hollow Light. You walk around a tiny planet. On the globe you stand on its outside, the way we normally picture a world. Press one button and it turns inside out: now you're standing on the inside of the shell, the sky is a blue bowl over your head, and the stars are a marble at the centre.

The two views are the same world under sphere inversion, the map that Hollow Light's bent light is built on. The ground stays put and everything above it changes size. A cliff too tall to climb on the globe becomes a short flight of steps in the cell, and a gap no one could jump closes up near the core. The other way round, a hut too small to squeeze into in the cell is roomy on the globe, and a star shard floating light-years out in space sits right next to the core. You stay the same size in both, so every level is about choosing which world to be in for each step. By the end you're flipping in mid-air to dive through a door, and ducking a sun that circles the core by flipping to the globe, where you're small enough for it to pass overhead.

Under the hood every piece of rock is a polar sector, and inversion maps sectors to sectors, so the collisions are exact in both worlds. The flip animation bends the world through flat: the ground's curvature slides from the globe's to the cell's while every height slides between its two values. There are ten levels, and each one ships with a scripted solution that a headless checker plays through. The promo above is rendered from those same scripts, frame by frame, with a synthesized soundtrack.

It sits alongside Hollow Golf (mini golf on the inside of the world) and Lightbender (a light-bending puzzle game).