Kill the Mafias from other family that is in the building. Mafias people will come out all over the building, pay attention on the windows because you will find them there the most. The moment you see the enemy you need to aim and shoot them as fast as possible before they shoot you. Be fast, be precise, be fast at the trigger like real mafia man and kill the enemies using your good old tommy gun and other weapons!
Use mouse to aim and fire.