A lot of the puzzles made it feel like I was literally banging my head against a wall.
In particular, I felt like sometimes I had to move an odd number of tiles in a straight line, but the nature of the movement makes that impossible. So the solution seemed to be to bang into a wal until I managed to "bounce" off by one tile, which then allowed me to move an even distance.
Other than that, though, I really like this concept, and I really appreciate the effort that went into level design. Seeing a stage again but with a lock and key added was pretty engaging.