This is a very good concept generally executed quite well, but these puzzles are *way* too finicky. People have talked about level 10 plenty, but level 11 is a particular bugbear personally. The complete erasure of progress because you failed to see one pusher is active is frustrating to the point of feeling player-hostile.
I feel like you can either demand perfect planning or perfect manual execution, but you definitely shouldn't be asking for both, especially not at the same time.