Point at things and make them dead. Wacky weapons, countless, mindless enemies, so hellbent on throwing in so many bodies that are fun to make fall down, that they occasionally miss the annoying long time until the soul spawns annoyance of graphics that are acceptable, but hardly stellar. But those points are minor at worst, considering the genius behind the innovation by stripping the FPS to its bare-boned, bloody minded glory.
This game should of gained full marks if they removed the story and voice acting entirely though. Not only are they terrible, but you get the all-to-depressing impression that they actually think they did a good job, by the third time your guy says "tastes like chicken", even the most violence loving 12 year old boy who's favorite game of all time is Manhunt will start thinking, "this is just in bad taste" If you can block that out and don't want any depth, give this a shot.