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