You know, most people would've run by now.
STORY:
Earth is under attack by aliens and the only one to stop them is Sam. Sam the Serious. Serious Sam. That's about it. Serious Sam story basically is about Sam's attempt to bring the fight to the alien boss lord.
GRAPHICS:
It's no Doom 3 per se. While some backgrounds are ok I gues, I found the visuals lacking. In some spots it even feels rushed. I wasn't impressed by the visuals, nor was I really satisfied. Cool boss fights though. And as for the aliens themselves, they could use some work (although the game is a bit old I guess).
MUSIC / SOUND EFFECTS:
Some plain nice music clips, and the sound effects are mostly comical (but there are some nice "normal" machine gun sounds as well, for instance). Sam makes comments on many occassions, and some of them are bound to make you smile ("Now THAT's ... a lot of bull.") From the introduction to the end, Sam does his best to make the game look silly, and in many cases, he succeeds.
GAMEPLAY:
Serious Sam is bsically two PC ports in one X-Box game. The first part is a normal shooter, while the latter has some weird stages, which I found a distraction, at best. All in all, the gameplay is fun, providing you with enough challenge, explosions and humour. There is a tremendous variety of enemies and weapons, so I don't have anything bad to say in this subject. Except perhaps that some enemies may require "annoying" methods of extermination.
OVERALL:
Serious Sam is not serious at all, but it IS fun to play. It may not be everyone's cup of tea, but I would recommend it to any shooter fan who wants "a shooter with a twist". Other than that, nothing to report.