Holy moly, this game's great. Music's good to listen to, the art looks good (especially for only using two colors), and the puzzles are just the right amount of difficult. Level 9, especially, took me a bit - but then was quite satisfying when I figured it out.
Some minor criticisms: first, the game is a bit laggy. I expect the player to move instantaneously, but the wee bit of lag I get makes it not feel very good in that regard.
Secondly (and take this less as a criticism and more as a suggestion, for if you ever continue this), it's not always easy to tell what an enemy is about to do next turn. Some visual indicators (such as facing the direction it's about to go) would be nice in that regard. Once I stuck around the level for a bit I was always able to figure out their patterns, but I'd like to be able to figure them out without waiting for them to do their whole loop.