Really like the pixel art and the music. And there is really a ton of content. Too bad that I don't have the time to solve all those puzzles, or I am not going to have enough time to check out all the other submissions.
What I didn't like is that many of the puzzles have a ton of identical tiles you can't really figure out any other way than through trial and error. Perhaps you could let the player place those interchangeably? It should be possible to detect identical tiles automatically.