Various cheats
     Cheats  are  activated  using command line arguments, so you must
run the game like this:

forces.exe -allmissions -cheatkeys 

Command line arguments are: 

-allmissions       Access to all mission 
-cheatkeys         Activates cheats keys. You can use them 
                   in the game, they are:

F3                 Turn INVUN on/off (invulnerability) 
F4                 Turn SMART on/off (kill every enemy in view with 1 shot)

Here is a list of other command line arguments:

notfullscreen 
demomode 
noembm 
nops 
safevs 
defaultmem 
nopuretnl 
nohwtnl 
noframescaleup 
noframewait 
do5p1 
nosplash 
skipintro 
screensize 
screenmode 
phase_text_used 
quickbreak 
debug 
extras 
cheatkeys 
antia 
multi2 
multi4 
edit 
particles 
noparticles 
limittexture 
localonly 
lodhud 
verbosehud 
nodamage 
singlestage 
nolensflare 
nosky 
framerate 
fileout 
keys 
mouse 
movie 
resetoptions 
no3dsound 
nosound 
alias 
latetextureload 
nodither 
nomipmap 
nobilinear 
notrilinear 
nofog 
nolighting 
lowdef 
noshadows 
nocd 
showloadingfilenames 
renewfile 
globalfile 
notauto 
no3dx 
nokni 
nowni 
notsc 
primary 
secondary 
compat 
storepad 
storeanims 
nolod 
autotgaconvert 
forcetgaload 
getfileinfo 
loadsfxeditcaps 
lowlod 
copylist 
filecopy 
fileextend 
view 
sensaura_demo 
sfxocclusion 
sfxcockpit 
sfxspecial 
sfxphantom 
sfxconic 
sfxnofrontend 
allmissions 
english 
french 
german 
spanish 
italian 
dutch 
swedish 
portuguese 
host 
join 
notimeout