All steps to enable Cheats must be performed after a mission has begun.

OVERVIEW:
To enable press and hold "Ctrl" and "F12" key simultaneously, repeat step 
to disable...(Overview shows big map of battlefield) 

RELOAD:
To enable press and hold "Alt" key, "Shift" key then "R" key simultaneously...
(Reload loads maximum amount of ammunition) 

REPAIR:
To enable press and hold "Alt" key, "Shift" key, then press "D" key 
simultaneously...(Repair lets you repair all damage) 

INDESTRUCTIBLE:
To enable press and hold "Alt" key, "Shift" key, then press "I" key 
simultaneously... (Indestructible makes your tank indestructible, each 
tank must be enabled separately) 

All Weapons, Unlimited Fuel and Health:
During the game, push [Backspace] and type “KYLE”.