Here is the full list of all 49 Alien Rage - Unlimited achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Complete single player campaign on Normal difficulty
Complete single player campaign on all difficulty levels
Play entire campaign using only 1 weapon
Play entire campaign using only the pistol
Complete single player campaign on Brutal difficulty
1000 Promethium Containers Destroyed
250 Kills With Melee
80 Kills While Piloting Mech
25 Kills Using Mech To Step On Enemies
500 Kills With Explosions
1500 Total Kills
Reach a player score of 50,000,000
Complete single player campaign on any difficulty level
Complete single player campaign on Hard difficulty
Defeat all Bosses
Defeat Vorus God Mech
Unlock all player perks
Defeat DF9 Sentry Mech
Find all audio recordings
500 Total Headshots
Destroy the security control room
Kill an enemy with every weapon
Use every weapon’s secondary fire mode
Use all weapons
Defeat Vorus Primus
Set the docking tower centrifuge to overdrive
Reach a player score of 25,000,000
Defeat GX-7 Destroyer Prototype
Defeat AA-19 Combat Mech
Defeat Mk XII Heavy Mech
Defeat Vorus Gladiator
Survive the Heavy room
Defeat Security Turrets
Take out the bunker
Defeat Vorus Centurion
Unlock first Perk
Lower the bridge
Find a new weapon
Find an alien weapon
Use any weapon’s secondary fire mode
Find all weapons
Join a multiplayer game
Win 10 multiplayer games
Get the most kills during a single multiplayer match
Get the most kills AND never die during a single multiplayer match
Play as a human in a multiplayer game
Play as an alien in a multiplayer game
Completely recover from damage 3 times during a multiplayer match
Never die during a single multiplayer match