Really good gameplay idea, reminds me of Bloxorz. Here's my feedback for you:
- Intro should be skippable, it is too long.
- Pixel art font doesn't fit into the art style.
- Walls should be in a little different color than the floor (just for more visual clarity), although this didn't make me enjoy the game less, it's just an opinion.
- Level animations / transitions look great and how levels fall apart when you fail as well, it adds some flavor to the game, but these animations last for way too long.
All in all, good job!