I'd make a super-violent first person shooter. The violence wouldn't be mindless though. You see, every enemy would lose limbs and chunks of skin with each shot. You'd start out just blowing arms and legs of human enemies, but later you'd fight giant mutants and stuff that would get ALL busted up before they finally went down. The strategy would be shooting off limbs that have super-powerful weapons, so it would be easier to blow away the rest of their body. I'd also try to give it an oldschool shooter feel. And by that I mean "PURE ADRENALINE RUSH!" You'd constantly be trapped in rooms with just you and the enemy and NO cover. You'd have to dodge there attacks while blowing them away at the same time, which was what oldschool was ALL about. Some rooms would have pillars to hide behind, but they'd take battle damage as well, and would give out quickly if you didn't take out the enemy fast. The controls would be pretty much like Halo, but I'd have WAY over the top weapons and power-ups, like cannons that shot little exploding cars, and bombs that cirlce you and blow up any enemies that get too close. The highlight of the game would be the screen-filling bosses that would make you say, "HOLY CRAP!" And after a while, "HE'S GOT NO ARMS AND HIS INTESTINES ARE HANGING OUT! HOW IS HE STILL SHOOTING AT ME!" And finally, "DUDE! THAT WAS THE SWEETEST VIDEOGAMING MOMENT OF MY LIFE!."