I like how the game sort of "throws you in at the deep end" and you learn what things do by experimenting with them. Really interesting and clever puzzles here and there, but the difficulty is all over the place. Level 6, for instance, requires much more thinking than level 7 or 8. Falling off the edges of the level is unnecessarily-frustrating, especially since sometimes you can click in the area of the "up-and-right" button, and it registers a click of the "down-and-right" button.
"Snap to grid" keyboard movement doesn't really work with isometric perspective. I'd have just left the directional buttons in the bottom-right and called it a day. Those are a really good idea; you should call more attention to them, if you use this scheme in the future (maybe have them change colour when the player pushes the arrow keys, if you decide to leave keyboard controls in.) I only figured out what they do on like level 9, lol. The on-screen buttons also got all jacked-up when I rotated the camera multiple times. Down-and-left became down-and-right, or maybe the opposite. Sometimes 180 degrees different, too.