It doesn't just build it. It proves it works.

Autopilot doesn't cheat its way to the end. It plays through the same controls a player uses: steer, jump, shoot, gather. Each run comes back as a Proof report: what passed, how often it won, the frame times, and anything that broke, with the object that caused it.

You write your own checks in plain words in the Playtest panel, like “the player can reach the exit in 15 seconds”, and they run every time.

The engine runs the game the same way frame for frame, so the same inputs give the same result. The bot finishes Castaway in 217.49 seconds on a Mac and in 217.49 seconds on a Steam Deck.

A building is split into rooms and the openings between them: doors and windows. Each frame the engine walks from the room you're in through the openings you can see, and leaves every other room out of the frame. Rooms near you stay on, lamps in unseen rooms fade out gently, and nothing pops.

In our old mansion test that took the dining room from 17 to 28 frames a second and the library from 19 to 31.

Switching features off to find what's slow throws the picture away. The Frame Doctor measures each stage of a frame live, without slowing it down, and names what's spending the time: which lamp's shadows are being redrawn and why, which objects are moving, how many lights reach each spot.

Then the fix is exact. One example from our haunted mansion: flickering candle flames kept swapping shadow slots, which cost 19 ms a frame; holding the slots steady took the mansion from 13 to 29 frames a second with the picture unchanged. While you play, a governor steps the least-visible settings first, measures each step, and takes back any step that didn't help.