Terracide Cheat Codes

(Enter under the Help Menu option in the Cheat Codes password box) 

barnsley = Invincible mode on/off
nozzle = Access to all episodes and levels through
the Game-Levels Menu option
popov = Go anywhere mode on/off
clam_chariot = Loads of cheats (including all guns)
welk = All guns available
phaal = Unlimited ammo on/off
batfinc = Full shields
drugssuck = Numbers displayed on screen on/off
top_trumps = "Go anywhere mode on" message displayed,
but it doesn't work
yams = "Go anywhere mode on" message displayed,
but it doesn't work

The following may also be cheat codes, but no message or effect was noticed.

activate
gimme_guns
Level
Episode
Options
Links
puff
frei
Pizza
Mobil
Energie
Camp
Otto
Klage
Hebel
gnade
bibel