Here is the full list of all 16 Psikodelya achievements.
Visit a new dimension.
Collect an acid.
Collect all acids.
Read a note.
Read all notes.
See a picture.
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!