Hold CTRL+ALT+SHFT while typing the below commands during Simulation:

cia - Unlimited ammo
coldmiser - Heat tracking off
dei - No idea what this does... "F E I F"
dorcs - Meet the DORCS!
enolagay - Nuke, one time use during simulation.
tlofront - Rear view camera becomes a front camera
hangaround - Something about a blimp. I think you hang around in the simulation even the time ended until you press these code again.
icanthackit - End mission
idkfa - Different means as icanthackit, but same result.
lairdo - Something about a blimp. No Idea.
meepmeep - Time compression key enabled
unmeepmeep - Time Compression Off
michelin - See the bounding spheres on debris and mech parts
mightymouse - Unlimited jumpjets
xray - X-Ray vision. Same as Enhance Imaging but you can see through walls/mountains, press "w" ones to disable it and reamain in Enhance Imaging Mode.
zmak - Time expansion enabled
blorb - Invulnerability
tinkerbell - Free-floating external cameras, press "C" to Disable