Quake 4

This is essentially the same game as Doom 3 except with the lights turned on and fewer monster closets. What both these games do well is provide tons of satisfying gun-play but with only the barest of story lines to keep you motivated to continue. I think the plot of this one was to find the big button that will win this war, but first find these three lesser (but still challenging) buttons. There is some variety in the form of a few turret and driving missions, but for the most part this is nine hours of pure arcade style run-and-gun action.