Excellent puzzle game - mechanics are taught clearly over the course of the first few levels and become really challenging as you progress - I got completely stuck on Careful as I've never been much good at these sorts of games, but it's clear that the puzzles are really well made.
The coin-on-side mechanic is very clever, and lends itself really well to some fiendish puzzles.
I particularly loved the stages that repeat with the only change being the coin's initial orientation, fantastic how much that impacts the solution!