Here is the full list of all 42 M.A.R.S. achievements.
Equip a drone in your loadout
In Multiplayer, save a total of 50 teammates from death
Kill 100 or more players in PVP Multiplayer
Complete a mission in nightmare difficulty
Complete a mission without dying
Fail a mission
Craft an Item.
Kill 500 Enemys with Grenades
Use 1000 silver bullets
Use 1000 gold bullets
Reach Level 5
Reach Level 10
Reach Level 15
Reach Level 35
Reach Level 50
Reach Level 100
Complete the Mercy Killing Map in Kill Every Thing 2.0 Mode on Easy Difficulty
Complete the Mercy Killing Map in Kill Every Thing 2.0 Mode on Normal Difficulty
Complete the Mercy Killing Map in Kill Every Thing 2.0 Mode on Hard Difficulty
Complete the Mercy Killing Map in Kill Every Thing 2.0 Mode on Nightmare Difficulty
Kill 200 Players in the PVP
Kill 10,000 players in PVP
Complete the map Big Dam Heroes on the Nightmare difficulty
Complete the map Sub-Optimal on the Nightmare difficulty.
Defeated Julia and Boris on the map Liberation '45
In the Head Hunter mode, achieve the largest head that you can hold above your shoulders
Revive teammates 100 times
Receive day 7 roll call rewards
Aquire your first epic rarity weapon
Have your drone reach level 25
Achieve MVP 1,000 times
Equip a Calling Card
Shoot for the first time in the Platinum Shooting Gallery
Upgrade a Legacy weapon all the way to Mk.5
Wear an Cosmetic Item in every Slot.
Complete any map on the Nightmare difficulty without using any teamwide revives
Kill 5000 Mechanical Enemies
Kill 5000 Human Enemies
Kill 5000 Brute Enemies
Kill 5000 Zombie Animal Enemies
Kill 5000 Zombie Enemies
Kill 5000 Zombie Brute Enemies