Serious Sam II Cheats
Hold R and press Black, White, Black, White, Black, White repeatedly at the main menu until the cheat option appears at the bottom. Then, pause your game and press X to access the cheat menu at the bottom of the pause menu. After cheats are activated, a message will appear in the top right part of the screen during game play. REMEMBER: The cheat...
Duke Nukem Forever reference
There are several passing remarks about a "Blonde guy taking forever". This a reference to the as-yet-to-be-published PC game Duke Nukem Forever.
How to beat Zum-Zum
On the level when you must defeat Zum-Zum, you must destroy all of the giant sunflowers so that Zum-Zum cannot regain its life. After you destroy the sunflowers, you can attack Zum-Zum and kill it before it recharges.
Lava stage Armor puzzle
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.