Here is the full list of all 39 Erra: Exordium achievements.
Finish your Adventure
Melt the protective shield of the alien object with lasers
Your health now regenerates
With backpack, you can carry an extra 10 rounds
Eliminate three hostiles by detonating the red fuel barrel. Mechatrons are known to go up in flames spectacularly
Shoot the chain on the chandelier and kill the Mechatron with it
Spot a star in the telescope
Use and Stan 15 enemies by EMI
Find an artifact that speeds up firearm reload
Find an artifact that extends enemies stun time
Kill your 10 enemies by using a hand grenade. Don't rush, if you don't want to die
Eliminate 10 drones using only cold weapons. Show them your skill
Find an artifact that increases attack speed
Collect 500 rounds
Eliminate 3 Enemy Units by using a mine detonation. Precise shot is all what you need
Destroy 69 soda cans
Defeat the Imgud
Shoot down 15 mines
Break 30 doors
Destroy 5 enemy missiles with firearms
It will help you to gain experience. Painful but still useful experience
Block 30 enemy melee attacks
Block 50 enemies attack
Block 20 enemy attacks with perfect timing. Do what must be done
Inflict 100 gunshot wounds on Mechatrons
Kill 25 Mechatrons with guns
Destroy 50 Mechatrons
Find and open 10 secret message capsules to reveal hidden treasures and important notes
Kill 25 Mechatrons with cold weapon
Find your first gun. You will need guns...lots of guns
Dive into your memory. Reclaim your past
Don’t miss posters, just witness the greatness
Brake 5 lamps