Gemini Wars sadly offers only a singleplayer campaign. A multiplayer or even a skirmish mode is nowhere to be seen. Players who love RTS-games with a nice story will however enjoy Gemini Wars.
There's still a bit of extra polish needed, not to mention, well, the rest of the game. If you like story and want to take yourself through the tale of the Gemini sector, then by all means give this game a go.
Unfortunately, I spent most of my experience with the title cursing in frustration at all the bugs, or wishing I was doing something -- anything -- other than sitting in front of my PC, watching ships move with the haste of a geriatric. With enough patches it could be a perfectly serviceable RTS, if not a particularly fun one.
Lost highlights are ever-the-same clashes of enormous fleet formations, during which tactical orders are either ignored or negated by mistakes in AI behavior. Lots of shortcomings as well as a number of bugs add to the frustration.