Re: So, How do you take over organised crime in Huson City?
Start by looking for a vacancy. Batman is a mixed curse. Sure, he's liable to take you down, but that means you can always look for an open territory where the last guys to attract his attention used to be. Then you can look for the weak mobster to move in on.
Offer to help him. He's weak and presumably losing ground unless things are quiet. If they are quiet, shoot someone important without letting anyone know there's a new player in town until later. That'll fix that. Offer, in return for a slice of his action to take down his threatening neighbour. That way, you've got both his territory and his neighbour's territory. Moving into the neighbour's territory you have two approaches. Massacres are appealing, but probably attract too much attention at this early point in the game. Instead you should rough up his street operators, show them that you are bigger and badder. At this point you want a show of force, but not an all-out war. Push them to the brink of war, then arrange a meeting between the three of you in which you negotiate new boundaries and make marketing and franchising deals that leave you on top. If you've got more firepower this gives you the upper hand, but firepower between gangs as between nations is better used as a threat than as an actuality. Cops, feds, vigilantes and bigger fish will all be attracted by the smell of blood. When a vigilante does show up however, it's important to take him or her down, particularly if they have the kind of gunslinger rep that will intimidate your colleagues because if you kill them, or even take them out of action for a while their rep becomes your rep. Eventually someone will decide enough is enough. A bigger fish will take notice of you, or a smaller one will refuse to see reason. Assuming that you aren't prepared to settle for less than the whole city, whack their top man and see if you can't deal with their successor. If they're cohesive and out to avenge their boss, it's massacre time.