Well, the only part of the game I had any issue with was the turtle, and that mostly came down to either not knowing where he should go or not knowing how to get him to a particular spot. The thing I did find interesting about this game was the use of multiple spawn points in a room being vital to solving each puzzle. At first I thought a few of these puzzles weren't possible, but finding out you keep your spot just outside where you enter a room and that the room doesn't reset made for some fun "Ah Ha!" moments. I don't know of any other tile sliders that use that.
tl;dr The turtle's usage felt a little vague. I liked that the puzzles weren't self contained and literally had you come at it from different angles.
Edit: My favorite room was probably the first giant bug room. That one has some clever movement.