I know how to force windowed mode in the game through a shortcut, but is there a way to get the Galaxy launcher to run the game windowed?

Bumping, because I'd really like to be able to play multiplayer in windowed mode.

Once you log in through Galaxy, you don't need the launcher every time. So, just run the game from AvP_Classic.exe, pass it the -w parameter and you're set. Multiplayer should still work.

All that said, this is one game where fullscreen really benefits the experience, as it's so dark.