Here is the full list of all 40 The Forgotten City achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Free the captive and shoot her captor with your gun
Lie 10 times
Allow Fabia to die in the collapsing temple
Reach the best ending with the smallest number of loops
Talk your way through every possible confrontation
Topple 10 peeled statues by kicking others into them
Die from hornet stings
Skip the city tour
Help Galerius romance Equitia
Reach Ending 3 of 4
Reach Ending 4 of 4
Assemble as many people as possible in the Museum
Intimidate the creator of The Golden Rule
Find all three missing persons
Solve Vergil's problem
Use Photo Mode
Confront the creator of The Golden Rule
Loop through time ten times
Have Duli released from his cell
Dodge 3 boulders
Discover what lies beneath the city
Read 10 different grafitti
Find treasure using the golden bow
Reach Ending 1 of 4
Finish the game without looping through time once
Reach Ending 2 of 4
Enter the upper cistern in an unconventional way
Trigger The Golden Rule by stealing 5 times
Steal 2000 coins after the Golden Rule is broken
Discover Underworld icons Sisyphus, Tantalus, Ixion and the Belide
Learn the true identity of the stranger by the river
Survive the Palace
Gild your first thing
Save Fabia's life
Get rejected by Aurelia
Pick up the sponge on a stick
Save Ulpius's life
Enter a villa with a daring leap
Save Iulia's life
Loop through time once