Couple of bugs I noticed:
-The camera angles in the right hallway of the map could be better. Some of the buildings are tall enough to block your view, especially during the zoomed in sections and when you move farther south. Left hallway doesn't have this problem.
-At some point while playing in the blue block mode, one of the jumping grey blocks couldn't be shot and appeared to be jumping one level above everything else. When it would get close, it would simply jump on top of the player block and stay there. Shooting up had no effect either. Would be neat to implement this as a kind of helicopter enemy in later levels if its not intended.
-White blocks only drop one coin when shot by a blue block. Again, might be intended.
-First time I played the game there were none of the drops I saw on later runs. Kills only rewarded with coins, which in turn only gave ammo through the shop, which was the only way to get more ammo. There were no dual-cannons or drugs or the like. I got to the third wave like this, so I don't think it was a case of "just missing it".
Otherwise it was very fun experience. Awaiting more updates in the future.