There are alot more codes but invulnerability is all I can remember. 


Ghost Bear's Legacy Invulnerability (Press) ctl+alt+shft (While Typing) kent

MechWarrior2 Invulnerability (Press) ctl+alt+shft (While Typing) blorb

MechWarrior2 Unlimited Ammo (Press) ctl+alt+shft (While Typing) cia