I love the small filesize. Can't get that with a commercial engine. The game itself works well as a 3D platformer. The various characters feel diverse, and the controls for the most part are nice. The air controls feel a bit too floaty, but that's really my only critique with the controls.
The map felt more like a test map/playground, meant more to show off what the characters could do and how they feel to control, rather than to be an actual game. Teleporters and 'size changers' having the same model felt a bit strange, but that's probably attributed to the game jam time limit more than anything.
I liked the visuals. The chunky low-framerate animations were my jam, though I do kind of wish that the rotation wasn't tied to the same framerate. It would be nice to have more instant feedback while turning.