Neat concept!
At first I thought it would be really hard since the game is in 2D and you have to mentalize every move you make, but it is easier than it looks.
The levels are well made to teach the mechanics and then to put this knowledge to the test! I did not feel like I was bruteforcing the solutions and it made me think to solve the levels!
The visual are nice and simple, the lack of music is a big help to concentrate and there is just the right amount of sound fx!
Well done!