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