Here is the full list of all 13 Neuronaut achievements.
Achieved by unlocking all the CG in the Gallery
Achieved by reaching all the possible endings
Achieved by reaching the Ending 7
Seduce Milana
Achieved by reaching the Ending 6
Achieved by reaching the Ending 5
Seduce Tessa
Seduce Lia
Achieved by reaching the Ending 4
Seduce Annie
Achieved by reaching the Ending 3
Achieved by reaching the Ending 2
Achieved by reaching the Ending 1