In order for you to play ShellShock Live on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 10.10 or above, SteamOS
Processor (CPU):
1.5 GHz or faster
Memory (RAM):
1 GB RAM
Graphics Card:
Shader model 2.0 capabilities; generally everything made since 2004 should work
Network:
Broadband Internet connection
Storage:
500 MB available space