Here is the full list of all 39 Nex Machina achievements.
Complete all achievements
Complete Techno Forest on Master difficulty
Complete 100 feats
Complete Arcade mode on Veteran difficulty
Complete Arcade mode on Experienced difficulty without continuing
Beat Machine City on Experienced difficulty in under 5:45
Earn 9 gold medals in the Arena
Complete 50 feats
Reach a multiplier of 50
Reach a human combo of 50
Clear a single world while succeeding in every end-level minigame on any difficulty
Save all Humans and Secret Humans in a single world on Veteran difficulty
Clear a single world on Experienced difficulty or higher without getting hit
Complete Space Station in arcade mode on any difficulty
Complete Arcade mode on Experienced difficulty
Earn 6 silver medals in the Arena
Finish 5 levels in a row without movement, dashing allowed
Defeat the Beamtron on Experienced difficulty with one or more enemies still alive
Dash through 3 beams with single dash
Earn 3 bronze medals in the Arena
Save all Secret Humans in a single world on Experienced difficulty or higher
Succeed in 10 end-level minigames in a row on any difficulty
Complete Future Labs in arcade mode on any difficulty
Complete Arcade mode on Rookie difficulty
Complete Machine City in arcade mode on any difficulty
Finish a level without firing your primary or your secondary weapon
Destroy every Secret Beacon in a single world
Complete Fire Caverns in arcade mode on any difficulty
Complete a single world on Experienced difficulty without saving any humans
Complete Crystal Mountain in arcade mode on any difficulty
Deal a killing blow to a boss with a Sword attack
Kill every Disruptor in a single world
Discover a secret level
Complete Techno Forest in arcade mode on any difficulty
Complete a feat
Fully power up the Hero
Reach a human combo of 5
Save a human while it's being harvested
Kill a Disruptor