Uh... this this is all right. Overall very basic. The premise has been done before, although the exact specifics are new. The controls seem a little slidey. I feel like there's not enough time spent with the "stack on top of each other" mechanic, although that could just be because I gave up when level 6 got frustrating. This does have potential, though. If you were to add some other interesting mechanics, it'd do more to catch my eye.