Cheats......please, use your skills/brains.
******* Partial Spoiler... do not read if you have not finished yet!!!*******
I admit I used cheats to finish the game. Lets face it, without the option to save the game at desired points playing some levels from scratch 10+ times just takes all joy factor out for me. Especially in the later chapters where the developers went away from a smart strategy using AI to Serious Sam types of play without the means to defend yourself only for the sake of extending the total time it takes to finish the game.
A perfect example being the Helo chapter aforementioned. This was my only complaint about the whole game experience. The AI was intelligent through the entire game. Minus the last few chapters at which point they just tossed in a million rocket shooting moron monsters... really dissapointing ending.