Here is the full list of all 17 ERSATZ achievements.
Completed Ersatz 100%
Beat any Journey Mode without getting a single Game Over screen
Beaten Journey Mode Beta in under 60 Minutes
Beaten Journey Mode Gamma in under 60 Minutes
Beaten Synth Rush ALL on any type
Beaten Type Gamma for the first time
'S' ranked every level in Type Gamma
Beaten Type Beta for the first time
'S' ranked every level in Type Beta
Beaten Journey Mode Alpha in Under 60 Minutes
'S' ranked every level in Type Alpha
Beaten Type Alpha for the first time
Collect all 8 hidden decryption keys
Unlocked the simulation "Synthesis"
Beat any Normal Mode level without taking a single hit
Achieved your first 'S' Rank
Completed the basic survival training