Here is the full list of all 12 Alien Hominid HD achievements.
Unlock all hats
Complete game on Insane difficulty
Complete game on Friendly difficulty
Defeat final boss without using a continue
Complete game on Normal difficulty
Destroy 25 buildings in one game
Attain 1000 kills during one game
10 consecutive head bites without touching the ground
Eat 50 KGB Agents with Yeti
Survive any challenge mode for 10 minutes
Reach 5000Km in Super Soviet Missile Mastar
Complete first level