Fun, concept, I liked it. That last level really had me stump for a bit. Funny enough I somehow missed that there was a tutorial; no fault of the game I didn't read the button and clicked on the 1.
My only feedback is the controls could be a bit more convenient. Seems like a keyboard only type of game. I would have preferred the dragging and undo to be mapped to keyboard keys and maybe holding a move key to keep moving.