Here is the full list of all 46 People Eater achievements.
Complete the tutorial.
Defeat the Machine.
Defeat the General.
Defeat the Fatcat.
Defeat the Hybrid.
Defeat the Specialist.
Escape the first facility with Eater.
Escape the first facility with Chomper.
Escape the first facility with Gorger.
Escape the first facility with Ingester.
Escape the first facility with Nibbler.
Escape the first facility with Devourer.
Escape the first facility with each of the six monsters.
Escape the second facility.
Escape the third facility.
Start a Challenge Mode run.
Escape the first facility in Challenge Mode.
Defeat the Machine without taking damage.
Defeat the General without taking damage.
Defeat the Fatcat without taking damage.
Defeat the Hybrid without taking damage.
Defeat the Specialist without taking damage.
Escape the first facility in under 17 minutes.
Escape the first facility in under 14 minutes.
Unlock 20 Adaptations.
Unlock 30 Adaptations.
Unlock 40 Adaptations.
Unlock all 50 Adaptations.
Emerge from Eater's shadow form beneath 5 enemies.
Destroy 5 rockets with Chomper's shockwave.
Melt 10 enemies with Gorger's acid.
Crush 15 enemies beneath Ingester's bones.
Eat 3 enemies stunned by one use of Nibbler's teleport.
Kill 20 enemies in a single bloodlust as Devourer.
Eat 1000 enemies total.
Eat 2500 enemies total.
Eat 5000 enemies total.
Eat 10000 enemies total.
Ascend 1000 meters total in elevators.
Ascend 2500 meters total in elevators.
Ascend 5000 meters total in elevators.
Ascend 10000 meters total in elevators.
Destroy 1000 doors total.
Spill 1000 gallons of water total.
Destroy 500 computers total.
Destroy 100 vehicles total.