The premise was easy to understand, and the puzzles offered surprising depth, especially with the added mechanics every few levels. I found myself going "Oooh" out loud a couple times. I liked the sound design, especially the "walking" sound effect. The only oversight I noticed is that the undo button is set to a physical location on the keyboard, so for me using a Swiss QWERTZ keyboard, undo was actually "Y". Other than that, great game!