The game is primarily a simulation game in the vein of Haemimont's game series Tropico, but the combat encounters found in the main missions, are resolved through a tactical Turn-Based Combat in the style of XCOM: Enemy Unknown.
The game later received a DLC expansion called "The Japanese Incentive", where the Boss deals with the Yakuza head Hikaro Eda and finds himself in a tragic romantic relationship with his trophy wife.
Omerta: City of Gangsters provides examples of:
- The Alcoholic: Doc O'Connel is one of these. The reason he became one is outlined in his bio—he used to be an upstanding doctor, but after one day when he couldn't save a kid (he did all he could, and the kid died while he was out from unrelated complications), he began diving into the bottle. After getting fired and running low on cash, he began treating mobsters to make ends meet, and ended up being a criminal himself, remaining blitzed at all times.
- Artificial Stupidity: The AI will often ignore cover and just charge your thugs and get slaughtered.
- Batter Up!: Many thugs carry baseball bats for weapons, and can inflict concussion and lessen your character's accuracy. On your own side, Big Man Johnson uses a bat as well.
- Bittersweet Ending: In the Japanese Incentive, the Boss gets his revenge for his first and last true love Mikoto, who dies in the penultimate chapter.
- Cold Sniper: Wolf, the assassin teammate you can recruit on Baltic Ave. is one, as his default weapon is a sniper rifle, and he maintains an image of ruthless efficiency.
- Combat Medic: Emmet "Doc" O'Connel can kick as much ass as anyone else and can revive fallen teammates while on combat missions.
- Cut and Paste Environments: There's only a limited number of maps used for the combat environments, and unless you use auto-resolve a lot, they'll be frequently repeated.
- Damn, It Feels Good to Be a Gangster!: The main campaign, in the Japanese Incentive...not so much.
- Dirty Cop: The police can be consistently bribed to leave you alone.
- Fatal Flaw: Mikoto's obsession with revenge against Mr. Eda.
- The Don: The main character starts out serving one named Louis Castaneda, but aspire to become the Don of Atlantic City.
- Drunken Master: Doc O'Connel seems to be able to still patch people up properly despite his constant drunkenness. In addition, while his aim leaves a bit to be desired, he's not completely useless with those revolvers of his either.
- Greedy Jew: Played painfully straight with Rabbi Hobsbaum, who will regularly try to haggle you down when selling him beer or liquor. The only thing that makes the portrayal somewhat palatable is that all the mob bosses are similarly broad ethnic stereotypes.
- The Irish Mob: Appears as sometime-allies, sometime-antagonists. There is also the named character of Ben O'Connor, a walking Oirish stereotype who will occasionally hit you up for guns to send to his "granny" in Ireland.
- Klingon Promotion: The mob adheres to this almost as a matter of principle.
- Kosher Nostra: Shows up occasionally, mostly linked to Rabbi Hobsbaum.
- The Mafia: The main character is trying to climb up the ranks in Atlantic City's organized crime circles.
- The Mafiya: Subverted. Alexi Lieven is Russian and a criminal, but not affiliated with the bratva. It is all but stated that he fought on the losing side in the October Revolution, fled to America and continued selling guns and liquor.
- Morale Mechanic: It is represented by the "Courage" bar, which will send a character fleeing when it is drained. Its size is determined by that character's "guts" stat.
- Multiple-Choice Past: The character creation process consists of a series of questions about your character and his past, such as the reason he left Italy for America. Your answers will then determine character's starting stats, as well as his preferred weapon type.
- Point Build System: Each character has stats like muscle, cunning, guts, etc. While you don't directly control their distribution when creating your character (see Multiple-Choice Past), you'll get to make these decisions when levelling up. Notably, all of the stats are combat-related, and will have no effect on the economic management part, even though it defines the majority of the game.
- The Roaring '20s: The game is set in this time period.
- Shout-Out: Various characters who can join your crew.
- The three Tucci brothers are a circle shout-out to Super Mario Bros.. Mario, the eldest, even introduces himself with "It's-a-me, Mario!" when you open his bio. The middle brother is Luigi, and the youngest seems to be a shout-out to Peach, with "Princess" as his nickname.
- Frank "Wolf" Joseph seems to be based off of Mr. Wolf from Pulp Fiction.
- Treacherous Advisor: Louis Castaneda takes you under his wing, in a sense, but tries to use you to kill a mob boss and let you take the fall for it while he climbs the ranks. You figure this out and turn the tables around on him, killing him instead and taking his place.
- Take Cover!: Cover points are present during combat. However, multiple reviews complained about their sparsity and illogical placement, to the pointed edge of a wall will fail to provide cover, whereas a nearby pillar will. Often, some of your thugs will be forced to stand out in the open, regardless.
- Traversible World Map: Both the main character, and his underlings, will need to walk on the map of the Atlantic City from their current location to the property you want to acquire and/or the place of a shoot-out. It's always done on foot, causing Metro reviewer to snark that any rich gangster with a car would have run you out of business in days.
- Villain with Good Publicity: You can gain better publicity amongst the populace through a range of charity acts. Interestingly, underground fight clubs will also increase your popularity, reflecting the views of the time.
- Yakuza: The focus of the Japanese Incentive expansion.
- You Kill It, You Bought It: You take over Louis Castaneda's position after you kill him.
