I love the "radial" Space Invaders twist. I gradually picked up on that if you moved, your bullets were thrown off the "mother ship," so to speak, and I'm digging the strategy element there of clearing enough enemies so that I could park and unload on the enemy and eventually nail it. Also, it didn't immediately dawn on me to go behind LOL, but that was cool realizing that and getting my head out of the Space Invaders box. Sweet design!
EDIT: Yikes! I just realized my review did not save. Fixed!