More of a tech demo than a game, so my comments are mostly in terms of aesthetic. This looks really nice! Especially the creepy cover. The third level in particular makes me feel like I'm in a lucid dream. I might recommend an option to cap it at 60 FPS because it kept jittering between 70 to 120 FPS for me.
Not going to be too harsh on the gameplay or anything, but I did make the box infinitely tumble twice somehow. Also regarding the theme, reality shifting seems unique for this jam from what I've played so far. I look forward to a full release.