Gameloft has launched N.O.V.A. 2 Near Orbit Vanguard Alliance (http://www.near-orbit-vanguard-alliance.com/) on the Mac App Store. It requires Mac OS X 10.6 and costs $9.99.
 
Here's how the game is described: "Six years have passed since the events depicted in the first episode. Humanity is now thrown into a bloody civil war fought on one side by the central government of the Terran Orbitals and the self-appointed Human-Alien Alliance; a new organization with a mysterious origin and agenda. Kal Wardin left active service in N.O.V.A. years ago and now lives among the colonists of the desert planet Scorpius. But war never spares even the most peaceful places."



N.O.V.A. 2 Near Orbit Vanguard Alliance offers 13 chapters, over a dozen weapons and three special powers (Freeze, Slow Time and Disc. You can have 1-10 players online or locally. The game has five modes (Free for All, Team Deathmatch, Capture the Flag, Freeze Tag, and InstaGib).