Use Titan Damage and Immortality, then make your way to Zeus's throne.
Go underneath his feet and shoot from there. He cannot reach you with
lightning or fire. Watch out for the smaller enemies.
I found that by pressing "Alt + 3" during game play, Will Rock was instantly
put in "god-mode". I have never played a 3D shooter with such an easy approach
to cheat codes, I am not complaining; I'm just glad that it works!