Serious gamers, enter here. Those looking for story time and tralala orchestral music don't bother.
This game is just pure action. There has never been a more frantic single player shooter. This game is as twitchy as an old-school top down space shooter. You need sharp reflexes to survive out there; they have headless kamikaze freaks after all.
Unlike many other shooters out there that give you many choices of guns yet restrict ammunition supply and kill your freedom, this game gives you plenty to shoot with. Unlike modern FPS games that pit you against small groups of sophisticated enemies that hide behind cover and whatnot, the enemies in this game are plumb stupid, but there are so many of them and they charge at you from all directions. The challenge here is far more exhilarating than any I've encountered in any modern shooter outside of perhaps Halo when it is at its finest.