This is Nova 2 (Near Orbital Vanguard Alliance) by Gameloft.
It is a legit version, not downloaded from the Apple Store so no passwords will be needed.
This game has been tested on Leoperd, Lion and Mountain Lion - all of them work
Your Mac must be bought after 2010 for all technical specification to be met.
Please Seed, this is a very good online multiplayer game with a great offline campaign story.
Nova 2 also resembles Halo 2 in many ways.
The game includes 10 stunning weapons that can be carried at the same time:
Dual Pistol, Assault Rifle, Pump-action Shotgun, Automatic Shotgun, Sniper Rifle, Rocket Launcher, Grenade Launcher, Alien Railgun, Alien Laser Rifle and Alien Gatling Gun.
Please download this game for the good of all mankind and I wish you luck in your future battles.