I seriously struggle at playing puzzle games so I didn't make it very far, but the puzzles are clearly well designed. Making puzzles is extremely difficult, so to make this many in 4 days it's crazy!
The music, while great, is very repetitive, I think for a game this long, there should have either been multiple tracks, or the main theme should have been much longer.
All in all, enjoyable game, I wish I was better at puzzles!