Here is the full list of all 19 Action Alien achievements.
Earn a total of 10 000 credits.
Kill 10 000 aliens.
Unlock all golden weapons.
Unlock all upgraded weapons.
Beat 100 aliens with leg kicks.
Unlock all perks.
Kill 15 boss aliens.
Complete the petrol station map.
Use every weapon during one game.
Kill an alien boss with the pistol.
Complete the tropical hotel map.
Blow up 500 aliens with grenades.
Kill 1 000 aliens.
Complete the wasteland map.
Blow up 8 aliens with one grenade.
Demolish a part of a building with the grenade launcher.
Kill an alien with the last bullet of a machine gun or an assault rifle.
Kill 100 aliens.
Empty all the rounds of a revolver with only deadly shots in less than 5 seconds.