Here is the full list of all 16 Jelly Killer achievements.
To escape a human body for the first time
To die 4 times at the same place
To enter a pipe holding control of a human being
To be impaled 32 times holding human body under control
To die 32 times
To take in all the five characters’ bodies
To destroy a body 32 times being close to the exit
To complete training
The quickest way to become a general
To get 8 headshots from turrets
To destroy 16 hazards holding control over a guardian
Kill a human with a rifle
An attempt to take control over a non-organic creature
To use a teleporter 8 times
To get into a wrong place
To complete the game