Anteroom
As soon as you enter this room the door freezes shut! You'll need to beat a handful of ghosts in this room. If you get hurt, shake the tables to get some hearts.
Wardrobe Room
Be careful of the green ghosts in here, they toss bananas on the floor. Step on a banana and Luigi will slip and fall on his rump. There four ghosts in the open. The last ghost is hiding in the closet in the right corner of the room. Shake the closet and the ghost will pop out. When the lights come on, a key can be found on top of the coat rack. Use your vacuum to collect it.
Small Balcony
Out on the balcony you'll find Toad crying. Give him a whassup and save your game. Head back to the Foyer. You now have a key to the door on the left. Before you can open the door the Professor warns you that the ghosts in the next room are tougher. Ignore the Professor. These ghosts are no match for Luigi.
Second Floor Hallway
Suck up the little ghost mice or they will end up hurting Luigi. The only door you can open is the first door you see.
Study **(Portrait Ghost - Neville)**
The ghost you need to beat is in the rocking chair. Books will be flying off the shelves so be sure not to get hit. Before defeating this ghost, there is a piece of cheese you will want to examine. Walk behind the desk and enter exploration mode by pressing X. Look for the piece of cheese and hit A. Exits eploration mode and a gold mouse will be running across the floor. Suck him up to get some cash. Remember that gold ghosts will only appear in dark (uncleared) rooms. Now it's time to take out the bookworm ghost. The ghost won't show up when you're looking at him. To catch the rocking chair ghost, step to the right side of him and have your back to him. He should stop reading his book and you'll see his heart. Turn quickly and suck him up. He's got 100 hit points so make sure to stay with him till he's finished. Open the chest that appears once the lights are on and get another key. Head to the door at the end of the hall and open it.
Master Bedroom **(Portrait Ghost - Lydia)**
This room's ghost is sitting at the bureau, combing her hair. This is an easy one to beat. Just vacuum the right curtain at the corner of the window to pull it back. There's a hole in the window that's causing a draft. The ghost will get up to close the curtain. Turn immediately and suck up the ghost. Her heart will only be exposed for a few moments. Once she's finished, the lights come on and you will retrieve another key from the treasure chest. Go back to the hallway and open the door closest to the one you just came out of.
Nursery **(Boss Ghost - Chauncey)**
You're about to meet the first boss, so get ready. If you're hurting, use the vacuum on the dresser next to the door. A big heart will appear fully healing you. Now it's time to meet baby. Use your vacuum on the rocking horse until the baby ghost appears. He may be cute, but he ain't cuddly. The teddy bears on the wall will begin flying at you, but they can be sucked up easily. See the ball on the floor? Suck it against your vacuum and then aim it at the baby. Let go of the R trigger and the ball will whack the kid in the head. 'Course, that just pisses him off. The baby shrinks Luigi and takes him to his crib.
The Crib **(Boss Ghost - Chauncey)**
The baby is cranky but pretty easy to beat. Baby ghost has three attacks to worry about. The first are rocking horses, which fly across the crib. They fly straight so simply move out of the way when they start to cross the crib. With the second attack, the ghost drops a few bouncing balls on the crib. Move around to avoid them. One of the balls will remain in the crib. Suck it up with your vacuum cleaner, aim it at the baby, and release the R trigger to whack the baby with the ball. He is now vulnerable, so turn on your vacuum cleaner and dust bust this crib crawler. You likely won't be able to completely deplete the ghost the first time. If you fail, he will do his third attack, which is a belly-flop bounce around the crib. Just stay clear of him and you'll be fine. Repeat the process until you have successfully defeated him. Back in the nursery, open the chest and take the pink key. The Professor will bring you back to his lab and show off his Ghost Portrificationizer, which turns captured boss ghosts into portraits. Congrats, you just beat the first area of Luigi's Mansion!