In these games, Luigi usually must use his flashlight to stun ghosts then suck them up. Most times, ghosts tend to drop items to halt the green hero's process. Also, whenever Luigi sucks up all the ghosts in one room, the room lights up and a treasure chest usually appears.
However, gameplay is much different in Luigi's Mansion: Dark Moon as, usually, rooms are already lit up when Luigi first enters but gets darken whenever a ghost appears. Also, the door gets locked and Luigi has no choice but to fight the ghosts. Also, Luigi explores five different mansions which all is separated into different missions. Now, Luigi must use the Strobulb to stun ghosts and the Dark-Light Device to stun Boos. It should also be noted that Luigi can use Golden Bones to revive himself whenever he loses all of his hearts.