First demo is Angry Bots game, recently published on Android. Download Angry Bots
Second demo has developed for tests, it's remake of classic game "Astroids" (known from Amiga console). Download Unitroids
More information about Linux games made with Unity can you found on our site.
English and German versions will be available in September. We looking for translators, if you feel that you can help, contact with us at mail gry [at] ubuntu-pomoc.org