Shadowrun for the Xbox 360 is a multiplayer only game that is similar to Counter-Strike or other team-based first person shooters. The game doesn't really have a single player mode so anyone that doesn't have a Xbox Live 360 account will not be able to play the game.
Shadowrun is a fairly underrated game and is actually a lot of fun; the team classes and weapons are all fairly balanced and the game has enough maps to not get old quick. The game could use a few more maps, some new weapons, and a new race or two but as it is now it's a fairly fun experience.
I've had quite a bit of fun playing online Shadowrun since it has been released and would recommend the game to anyone that enjoys team-based online shooters and is looking for something a bit new and unique.