In Luigi's Mansion, the main story is played out over four stages, with players able to also access a training room and a gallery at Professor E. Gadd's laboratory between stages.[1] In each stage, players control Luigi as he explores the mansion's rooms and hunts down the ghosts that lie within them, acquiring keys to get through locked doors and eventually dealing with a boss ghost hidden at the end of the stage, with more rooms becoming accessible as each stage is completed. To assist him in his task, Luigi uses a flashlightand two inventions supplied by E. Gadd – the Poltergust 3000, a specially modified, high-powered vacuum cleaner; and the Game Boy Horror, a play on Nintendo's Game Boy Color.
In order to capture ghosts, Luigi must first use his flashlight to light up the ghost and stun it, revealing its heart. When this happens, players use the Poltergust 3000 to suck them up, steadily reducing the ghost's hit points to zero; the more hit points, the more time it takes for a ghost to be captured, giving them a chance to break free while leaving Luigi more exposed to being harmed. If Luigi's HP is reduced to zero from being hurt by the ghosts, the game is over. Once a ghost's HP is reduced to zero, they are captured.[2] Some ghosts cannot be captured easily until Luigi locates three special medallions, each granting the Poltergust with the ability to suck up certain elements from the rooms and use them to capture special ghosts lying within the mansion.[3] In addition to capturing the regular ghosts in the mansion, Luigi must also draw out special "portrait ghosts" from some rooms, each requiring a condition be met to make them available for capture. Once all the ghosts in a room are captured, it brightens up. The music also changes accordingly, being pleasantly whistled by Luigi, while being haunted and spooky when filled with ghosts, with Luigi humming nervously to the tune.
Utilizing the Game Boy Horror, players can access a map of the mansion, seeing which rooms they have visited, what doors are open, and which remain locked. When Luigi finds a key during his explorations, the Game Boy Horror automatically indicates which door it unlocks.[4] In addition to a map function, the device also keeps track of any treasure that Luigi has found – rooms will usually have treasure hidden within, which can be either coins, gems, gold bars and so forth, hidden within items and even in a chest that appears when the ghosts are cleared out, which Luigi can draw out and suck up with the Poltergust; if a ghost harms Luigi, he will drop a small portion of the collected treasure that he will need to recover before it disappears. After Luigi encounters a group of Boos hiding in the mansion, the device can be used to find each one hiding in a room, through a beeper sound and a flashing yellow light on the device, which turns red when Luigi is close to one; Boos can only be located in rooms that have become lit after their ghosts have been cleared out.[4] Boos are trickier to deal with, as they can plant decoys and traps within objects they can hide in that can fool the Horror, and will escape into other rooms if they can, forcing the player to chase after them.
Once a stage is completed, all portrait ghosts are restored to their paintings by E. Gadd, which the player can view in his laboratory's gallery,[5] at which point a result screen reveals the portrait ghosts Luigi has managed to capture, along with the total amount of treasure he recovered for that stage. Once the final boss of Luigi's Mansion is defeated, the player is given a rating (A to H) during the end credits, based on the amount of treasure Luigi has found. After completing the game once, a second mode is offered, called the "Hidden Mansion". In the European version of this mode, the mansion appears as a reflection of the previous version, with bosses being made more difficult, ghosts and Portrait Ghosts being trickier to capture, and more ghosts being in some of the rooms.
