Thank You for these games, There are many others like:
1. 0 A.D.
3. Alien Arena
4. Armagetron Advanced
The Open Source games are just amazing.
Thanks for the info, Exactly Raspberry Pi is a great device can be used for many projects (I mean any project as you can think) like: Android TV Box ; Media Center Server ; Network Ads Blocker ; ChromeCast device ; and others ...; It's realy nice and its cost make it ideal.
You can take a look to other projects on my site.