The game is really good! here's a few bits of advice: you can change your sprites' rendering filter to point(no filter) instead of Bilinear in unity so the pixel art won't be blury (you can add a pixel perfect camera component too.)
Regarding game design, it wasn't obvious in the third or fourth level that I just simply could walk into a wall to cancel my move since it was highlighted with red.
Other than that good job!