Source: http://store.steampowered.com/news/3335/Aliens vs. Predator Classic 2000 brings three most ferocious species in the universe together in a bloodthirsty battle for the ultimate prize: survival. Take your pick: be a Colonial Marine, a Predator or an Alien. Fight through suspense-filled environments: from starships and space stations to colonial bases and eerie planetscapes. One wrong move turns you from hunter to prey.
With Aliens vs. Predator (a reboot of the series) a month away from release, this is a good opportunity to become acquainted/reacquainted with the series.
It looks like it only comes with the singleplayer campaign, but no multiplayer. However, from what I can find, multiplayer will be added later.