During play, press CTRL+X to enable a cheat menu. Now type:

cavalry   -   Invincible
hemmit    -   All Weapons
medic     -   100% Shields

health    -   Full health   
ammo      -   Unlimited ammuntion  
killjoy   -   Extra hover tech  

Thanks to Revolution readers Roy Kockelkoren, Viraj Pradhan and Marc Kluyskens!