Here is the full list of all 20 Nystagmus achievements.
Find the wedding ring
Make the right decision
Write diary at every campfire
Find a copy of Jacob Hayes Was Gone Today
Find the Fish Toy
Find the storybook
Find the Soul Flask
Complete the game with bad ending
Find the Driver License
Find the Vtopia Game
Find the music box
Kill yourself in a dumb way
Find the necklace
Collect all 60 notes
Complete game and leave the island
Have a near death experience
Find a upside down cross
Find the inkwell
Find the other half of the picture
Get closer to the monster