Omerta is a massive multiplayer mafia game. The action takes place in a crowded city in the 1930's. Working legally you will hardly earn for living. You choose the other way - to be a gangster. It is a risky way, but if you're inteligent and lucky enough, you can rise to the Godfather of the city...
Starting as a pickpocket you raise your respect and little by little, get more activities to do - steal cars, set up illegal fights. If you are strong enough, you even can set up a chop shop or casino.
In Omerta, like in the real world, respect and allies are everything. You can join or create a family. Families can compete in the city for extortions and illegal markets. Sometimes competition gets too big and there is no other way to lower it than to start a family war. Robbings, fights, whack attempts, arsoning - everything goes in times of war.