The player is able to re-enter the portal they had entered from and restart the time loop if the Golden Rule is ever enacted, allowing them to keep both physical and mental objects such as important items and information.

The plot was significantly altered from its original story in the mod, with the setting of a Dwemer ruin being shifted towards that of ancient Rome as well as much of the script being updated and rewritten.

[30] IGN awarded the game a 9/10 stating: "The Forgotten City does a fabulous job exploring interesting moral quandaries through excellently written dialogue and characters.

"[21] Luke Holland of The Guardian gave it 4/5 stars, writing that despite minor technical issues, "The Forgotten City is a tremendous achievement, a labyrinthine little sandbox packed with interpersonal mysteries", which "unravel further and further with each pass.

"[31] GameSpot liked the progression the player had within the loop, writing, "It's satisfying the first time you find these solutions, but even more so when you see how each one acts as a piece of the larger puzzle, opening new avenues for you to investigate in the process.

"[20] Eurogamer praised the connections each individual mystery had to each other "The time loop itself leads to some wonderful stuff, though, linking itself into puzzles in ingenious ways".

[18] PC Gamer liked the way the player could bend the game's morality system, but criticized the combat as clunky and uninteresting, saying there was a "sequence where I had to skulk through a ruined palace filled with creepy animated statues...

"[24] Push Square wrote similarly and gave the game 7/10 stars, concluding, "With the interesting time loop mechanic creating further situations full of comedy and intrigue, settling down across a few evenings with The Forgotten City will delight.