There are several command line options that can be used to tweak Galactic Civilizations II. Not all appear to be functional or useful.
They should be added to the Target of a shortcut to the GalCiv2.exe file, as so:
"C:\Program Files\Stardock\Totalgaming.net\Galciv2.exe" w cheat
- CHEAT - enables cheats
- W - sets windowed mode
- MOUSE - enables the software mouse?
- FRAMERATE - displays the framerate
- SCREENDATA - ?
- DEBUG - enables debug mode (more output to debug.err)
- QUICKSTART - starts a new game immediately
- AITEST - intended to enable the AI testing mode without the use of a cheat key, but appears to just break the game
- NOPOINTSPRITES - disables point sprites?