Wow! So much content, super varied, super interesting puzzle solving, and your own engine. Super impressed. Wasn't expecting diagonal paths either, which made everything (including your animation needs) higher. Loved this one. Even the chiptune bossa nova was very charming.
My one nitpick ( so small) is that I didn't notice that you had a limited number of paths until maybe 4 or 5 levels in, so when I tried to make a new path with 0 left, I got confused and thought the game was bugging. Some kind of "no you can't do that" feedback to the player when they try would be the best way to get that across imo!