X-Trem OS isn't really that much. It is a rare GUI since it is in German, and it runs in SCREEN 13. I had a little trouble with the installation, so some features might not work well. The programs that come with X-Trem OS have to be added manually to the menu on start-up of the GUI. The windowing system is interesting too, since all of the windows created in X-Trem OS are closed with the right-button and dragged with the left. No minimizing, but they do have task bar buttons. This is an interesting GUI to download.