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