If you're going to play Serious Sam, Croteam's riotous PC/Xbox FPS, through to completion, it's hardly going to leave you with any thorny existential questions to ponder. It's a game that's giddying in its simplicity. Several billion (well, many dozen) enemies spawn and charge/shoot at you, and you shoot back at them, endlessly circle-strafing and pumping the trigger in a gloriously dumb haze of gunfire and death yelps. And that's it, over and over, for the entire game. Zero subtlety. Minimal variation. On paper, it's deafeningly flat. It's the action-hero equivalent of LOLspeak. So, if you play Serious Sam through to completion, you are actually left with something to ponder: what the hell am I doing?