Here is the full list of all 16 Psikodelya achievements.
Read a note.
See a picture.
Collect an acid.
Visit a new dimension.
Collect all acids.
Read all notes.
See all pictures.
Open all portals.
Die falling into the void.
Visit the purple swamp.
Visit the Neon Box.
Tried to swim in lava.
Enter the maze.
Die in a trap.
This is the end, beautiful friend.
And the truth shall make you mad. 100% complete!