Here is the full list of all 16 Jelly Killer achievements.
To complete training
To take in all the five characters’ bodies
To die 32 times
The quickest way to become a general
To enter a pipe holding control of a human being
To escape a human body for the first time
To be impaled 32 times holding human body under control
To destroy a body 32 times being close to the exit
To die 4 times at the same place
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