Awfully Quiet
I like the idea of this game, I've played similar games but I enjoy what you do different with the minions, and powerups like the overlords, bombs and skulls. The game though is very silent except for the powerups making any sort of noise. It could use some background music, and possibly show the game in rounds in between waves of minions to give people a viewpoint of where they stand game wise. You could have an unlimited number of rounds just as long as you number them when someone's cleared out all the minions it helps get a grip of how they're doing. There isn't much of a preloader and I didn't really pay attention to the sidebar right away. Just things to think over if you ever plan on revising or creating a sequel. Good game though.