The best linux game I know is overkill. Great! Loads of blood, weapons, bullets and brackets...
For best graphics experience, you'll definitely need a black backgrounded terminal.
As you were talking about downtime: make sure to start some bots with your overkill-server.
Btw: Does anyone know a public overkill server, which is still running? Those listed on the project home page all seem to be down
Screenshot (only the eyes of the main character):
[censored due to