Here is the full list of all 13 GabeN: The Final Decision achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Congratulations! You beat GabeN: The Final Decision! Feel free to uninstall.
Ok so now you defeated the Illuminati! Congrats! Now you can release Half Life 3! Or can you...
Utterly destroy that illuminati boss!
Finally, you defeated the Illuminati! Or did you...
Kill the last admin alive, Wallace Breen.
KIll that commander with your sick burns! (Mixtape not included)
Destroy the Combine Tank guarding the eastern gate!
Completely wreck that commander!
Defeat the Xen Leader, Nihilanth!
Kill GLaDOS and shut down her systems.
Defeat that traitor!
Kill the Administrator before she relays her dangerous information to the rest of the admins!
Unlocked by starting a new game.