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