What I liked: It reminded me more of a physical puzzle than a typical video game puzzle. Probably due to that lack of feedback / visuals. This made it frustrating but also surprisingly zen. I played it a lot longer than I thought I would and overall I really enjoyed it.
What I would suggest: I think making it so you move along a grid like chess would make it less frustrating. It would also make it much easier but the difficulty could be ramped up with hazards and harder level design.