Here is the full list of all 57 It came from space, and ate our brains achievements.
Complete all Campaign levels on Hard
Complete all Campaign levels on Easy
Complete all Campaign levels on Medium
Complete Cave (Campaign) on any difficulty
Complete Riverside (Campaign) on any difficulty
Complete Sewers (Campaign) on any difficulty
Complete Alleys (Campaign) on any difficulty
Complete Clinic (Campaign) on any difficulty
Complete Rooftops (Campaign) on any difficulty
Finish the first six levels on hard.
Finish with the highest score in a multiplayer game 10 times.
Finish the first six levels on insane.
Finish 6 multiplayer games on insane without dying.
Died 123 times.
Shoot 95471 times.
Finish the first six levels on medium.
Place 15 mines.
Revive 5 people using medkits.
Finish 3 multiplayer games on insane without dying.
Place 5 turrets.
Finish 1 multiplayer game on insane without dying.
Staying alive while other players are waiting to respawn.
Use the searchlights 5 times.
Use the shield 5 times.
Finish block ship on any difficulty.
Finish block launchpad on any difficulty.
Finish block scrapyard on any difficulty.
Reach 75x multiplier.
Finish block suburbs on any difficulty.
Finish block industrial on any difficulty.
Finish block navy on any difficulty.
Finish block planet on any difficulty.
Finish the first six levels on easy.
Kill 10000 aliens.
Finish block crash site on any difficulty.
Finish block countryside on any difficulty.
Reach 50x multiplier.
Finish block highway on any difficulty.
Buy all rocketlauncher upgrades.
Buy all shotgun upgrades.
Reach 25x multiplier.
Finish block city on any difficulty.
Finish with the highest score in a multiplayer game.
Buy all pistol upgrades.
Pick up 100 upgrades dropped by the S.W.A.T. Drone.
Buy all plasmagun upgrades.
Finish block hospital on any difficulty.
Kill 7 aliens at once.
Buy all laser upgrades.
Kill 1338 crawlers.
Buy all machinegun upgrades.
Kill 1000 aliens.
Kill an enemy close to a player with one health.
Die for the first time.
Kill 100000 aliens.
Make 25.000.000 amount of Coins in total.
Complete all Campaign levels on Insane