Good UI, excellent onboarding (perhaps just a bit too slow?). The main problem is that puzzles just aren't engaging - the player can see exactly what the solution is, but execution of the solution is not particularly engaging. The red blocks added some interresting game play but once you introduced back tracking (keys) we stopped playing. Great effort!

I'm curious what the tech stack is - is this a custom engine? How does such a simple game end up being 290+ MB?