I hate that most FPS don't have a decent story. Sure,all you do is kill something and the story usual falls down into one of these plots:
1) Aliens are invading, kill them all.
2) You are in the army trying to kill Hitler's forces.
3) Military forces where the government sends you in for the job they cant do.
4) Someone you loved is dead, seek revenge.
I may play this if the game is pretty decent in terms of violence and gore isn't over exaggerated.