I think the concept here (gravity manipulation across fixed-size screens) is awesome. Unfortunately I think the game opened up way too quickly - the moment you get gravity manipulation you suddenly have access to several different puzzles. The very first one of making a colored tile reach a square was fine, but they quickly ramped up in complexity in a way where I couldn't tell if I was missing powers or if I simply didn't understand what was going on. The hitboxes of the "kill the box" red zap tiles were very large and unforgiving for a game where you don't have tile-precise control over the box's trajectories. Coupling in the occasional "critical object clipping out of bounds" and I ultimately somehow wrapped back around to one of the starting rooms and backed out. I'd need to watch the solutions video I think.
I did play on the RapierWeb build. Physics seemed mostly stable, but with the occasional clipping or lag spikes as a lot happened in quick succession - truly not sure what to do about those issues except for aggressive OoB checks for critical objects haha.
While the current state makes sense from a minimalism perspective, I think I'd really love this concept if you gave the relevant puzzle rooms some more breathing space - with simpler navigation rooms between them, and expanding the world out to more gradually introduce the mechanics. Later on would be a great spot to have the more tightly interwoven puzzle screens, once the player has already come to grips with the basic systems. This is an *extremely* good idea you could do a ton more with, and I'd love to see it.