Aliens
Aliens, eh? If they're not abducting you and conducting embarrassingly intrusive experiments on your colonic region, they're jumping headlong into your gun sights just begging to have their insides outed by your shotgun. They've been doing it since 1978 with Space Invaders, and we still love them.
The original Space Invaders were based on sea creatures (if you look at their pixellated forms in the pic below, you'll see what we mean), but later enemies have been much more varied. From the classic Greys of Area 51 to the toothy-grinned Chimera of Resistance: Fall of Man, there's something for everyone. And with no 'they're human so it's wrong' stigma attached, even kiddies can enjoy some alien-smashing action. Hooray!
Above: Halo, Space Invaders, Area 51 and Resistance: Fall of Man
