A couple of changes, and you have a solid game.
I think this could be a solid game if two obvious things are changed. Get rid of the swastikas, change the kittens into bombs, and you have something that's less pointlessly offensive. Then you could make it into a standard defense game, with upgrades and the like, and maybe make it into the collection. My only other complaints is that the lag gets nasty and the sounds get annoying.