Here is the full list of all 12 Fortix achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Finish the game on Impossible difficulty.
Complete every level to perfect on any difficulty.
Capture 100 dragons.
Capture Xitrof.
Let Xitrof lay 15 eggs on the final level, then win the level.
Capture one of each enemies.
Capture 100 powerups.
Destroy all towers (at least 2) on a level with a single capture.
Capture a powerup while you are under the effect of an other powerup.
Capture a catapult trigger when there is no more turret left to shoot out.
Capture at least 3 triggers with one capture.
Conquer at least 40% of the playfield with a single capture.