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