I bought it. It's a pretty darn good puzzle game. You're put in a room, and you have to get to the exit within a certain time. When the time runs out, the level starts again, and you play alongside a ghost which repeats your actions on the previous run. So you have to work with the your past selves to get to the exit. This means that getting out of the room and solving the puzzles is pretty damn easy, but doing it with the minimum amount of ghosts is where the challenge comes in. Usually 3 ghosts are required to get the highest rating, but sometimes it's 2 or 4. I'm about 20 levels in, out of 56, and a couple of them have taken quite a while to figure out.
There's a good amount of puzzle object to get around as well. Buttons to push, buttons to stand on, sets of buttons where the right on to push is random, walls that disappear for a set amount of time, spiky blocks that follow you when you don't look at them (Mario ghosts basically), bounce pads, holes, etc etc.
You need to spend quite a bit of time with the trickier levels, since you're not just working with your past actions, but also have to predict how long your future actions will take. Your first ghost might need to do a lot of work, but you can't rerecord individual ghosts, so if you need to stand on a button to make a platform appear, and then go and do something else, you need to know how much time your second ghost will take to cross that platform. Not being able to rerecord means if you bugger something up you have to restart the whole level, you can't just restart the last recording. It's pretty satisfying when it works though, because the first run can look pretty random on it's own, but then it all comes together perfectly.
Each level has 2 extra variations as well. There's a normal one, where you just complete the level, one where you have to complete the level and collect a key, and one where you get the ability to stop the clock for a total of 3 seconds, for speed runs. Which is more complicated than it sounds, since stopping the clock means your movement is not recorded. If you stop the clock with your first ghost and walk along a bit, on your second run the first ghost will just teleport from where they stopped the clock to where they started it again.
Good game.