I like the idea! The art and colour schemes were really well put together also. I agree with Nam who commented here about making it clearer which button affects what. On top of that, I would suggest making it possible to lower the propelling platforms if you shot their button prematurely (it's difficult not to shoot on sight!). In addition, perhaps make it clearer that the falling debris should be shot. It took me four tries to realise that that was what was expected of me. Perhaps you could do this by making the debris the same colours as the 'shoot me' buttons, or drawing an arrow on the background pointing at the garbage chute saying 'shoot me'.
I really think that this concept has a lot of potential! Good on you for putting such a polished game together in 48 hours.