how do i play against another person

Simply put: You don't.

You can create a Metaverse character (linked to your email and serial number), then play a game using the Metaverse button. This disables a things like custom scenarios and mods, but in the end, your score gets uploaded to the Stardock servers.

Then, you can compare yourself to other players, but this is indirect. Once they come back, you can also display medals and achievements based on your Metaverse games along with your forum posts.

In addition if you have Twilight of the Arnor, you can participate in the tournaments where you can compare your metaverse score with others who played on the exact same map.

Also once you're a bit familiar with the game, feel free to join the Metaverse League which is some sort of monthly team competition - very enjoyable and from experience I'd say you learn a lot about GalCiv2 tactics.

If its any sort of consolation, even a medium sized game probably would have lasted several months anyway. Yeah, that...that is not much consolation. ... (awkward pause)...(fake cough)...(more awkward pause).

The only thing you can do is play a quasi-hotseat game on one computer. You basically use a cheat to be able to control enemy races as well. So you activate this for another race and when the other race makes it moves you just let it be done by a friend of yours. This way you can play kind of multiplayer games on one computer. BUt basically GCII is not thought to be a multiplayer game.

Look at these links to find out how cheats are enabled:

Gal Civ 2 Cheats
How to: Hotseat game

So technically you could have up to 10 people playing?