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