Got through level 30, paused the game, tried to get to the menu, an got a browser crash.
Decent puzzle, but graphics are too basic. The horizontal and vertical scaling should match to make square grid. When you grab a piece and move it its spot, you don't see an empty space left behind until you finish the jump. When failing a puzzle, the "retry" screen should show the ending position; the transition is too quick/harsh. The sound is pretty bad. If there is a basic instruction/rules page, I missed it.