Nothing but Fun!
Croteam (The people who made Serious Sam) decided that the console gamers deserved a piece of the action, so they made a console version. Serious Sam for the Xbox, in many ways, is pretty much the same as the PC versions. It has all the levels of the first and second encounter plus they've added a few little features.
One of these new features is the combo system. The more enemies you kill with one shot of a weapon, the more points are added to your combo. This feature doesn't interfere with the game in any way, it just enhances it a little.
The Xbox version of Serious Sam does not have a quicksave option. Instead, it has been replaced with a lives system. You get lives by gaining points. Simple. 100 000 points give you one extra life. They've also added a few humorous cutscenes between levels and some of them are quite funny.
Many people liked this game because of the battles against what seemed like thousands of enemies. The Xbox version still has all of these gigantic battles, and some have even had more enemies added.
The graphics in this version of Serious Sam are very good and even rival the PC version in some areas. Some of the enemies have had their look updated a little bit. It doesn't even lose a lot of frame rate during heated battles!
The sound is pretty much the same as the PC version, and that's all you need to know.
Serious Sam for the Xbox is pretty faithful to the PC versions, and I like it! I recommend it to anyone who likes old-school arcade games and people who just like shooting stuff.