I like this type of puzzle, and the graphics and sound design on top of it are great! The challenge is seems fair for each difficulty, but can anyone confirm that Level 3 is possible on hard mode? I couldn't find any solution. Good job!
I can confirm that I also couldn't complete level 3 on hard mode if that helps at all haha.
I guess if you want to make it doable you could just change the tiles needed to 39 instead of 40, that's possible!