Here is the full list of all 51 Gabriel Knight: Sins of the Fathers 20th Anniversary Edition achievements.
Enter the ceremony alone
Don't try to save Malia
Complete with game with a full score of 362 points
Have your fortune told
Complete the game with less than 362 points
Complete Day 10
Try to save Malia
Enter the secret Voodoo Hounfour
Enter the ceremony with back-up
Complete Day 9
Complete Day 8
Collect all the tiles
Get past the mummies like a true adventurer!
Complete your research
Open a secret door
Complete day 7
Complete the intiation ceremony
Discover a shocking loss
Complete Day 6
Have a long chat with Wolfgang
Leave your own Voodoo code message
Get inside Mosely's Office
Decode the rada drum message
Hide the tracker
Complete Day 5
Translate a mysterious code
Change Mosely's mind about the Voodoo Murders Case
Survive the deadly python
Take in a snake dance performance
Read Gunter's journal
Complete Day 4
Find Madame Cazaunoux's address
Have a fated run-in
Make a jewelry mold
Sit through the Voodoo lecture
Complete Day 3
Compliment Gran as thoroughly as she deserves
Witness a chilling death
Find the secrets of Granddaddy's Clock
Help Sam improve his game
Make a large purchase from Willy
Complete Day 2
Exhaust Dr. John on the topic of Voodoo
Excessive flirting!
Get a copy of the Voodoo Murders File
Obtain a false ID
Complete Day 1
Find a clue at Lake Pontchartrain
Meet Malia Gedde
Get rid of the cop in Jackson Square
Read the Paper on Day 1