Serious Sam 2

To unlock the cheats go to the main menu.
While holding the right trigger, press:
White + Black + White + White + Black + White + Black + White

The cheats menu can be accessed by pressing F1

Armor in Lava stage:
Just before you get the mini-gun, there is a door on your right.
Open it and there will be armor on the other side.
You must to step on the correct letters; the order is: S, E, R, I, O, U, S.

Duke Nukem Forever reference:
There are several passing remarks in the game about a "Blonde guy
taking forever". This a reference to the as-yet-to-be-published
PC game Duke Nukem Forever.

 