- Luigi gets easily scared, especially when ghosts are involved, as introduced in this game. Everything about the mansion and the ghost scare him senseless, so if he wants to leave Boo Woods immediately, it's understandable, but even though Professor E. Gadd tells him that the mansion is an illusion and Mario went in without listening to his warnings, he doesn't. Then why does he still fight ghosts with the Poltergust 3000, facing the things that scare him the most in the middle of a dark and stormy night? Because this is personal. Mario has gone missing, and he won't leave until he finds him and brings him back home safe and sound, adamantly refusing to escape without rescuing him first.
- The ending of the game, when Luigi has finally gotten Mario's painting back after a horrifying night. The Prof. decides to use his machine in reverse, sending Mario through a ridiculous course with much comedic hollering. What makes this a heartwarming moment, however, is Luigi's reaction when Mario bursts out the other end of the machine, fully alive, but with a grate stuck over his head. Luigi just stands in silence for a moment with his mouth open in a wide smile, like he can't believe it, and then tears start rolling down his face as he slowly bursts into a most heavily relieved laugh, with tears still rolling down his face all the while. When you've gone through the events Luigi has, overcoming his fear for his brother... That one moment makes it all worthwhile.Luigi: ...hohohohoho... Hohohoho... Oohoho, Ahahahahaha... OOHAHAHAHAHA, AHAHAHAHAHAH! Ohohohohoho, oh, Mario...
- It crosses into being a happy kind of Tear Jerker - Luigi has spent the entire game terrified out of his mind facing a very different kind of threat neither of them had dealt with before, all to save his normally unstoppable brother. Luigi's reaction to seeing Mario pop out of that Portrificationizer really feels like the relief of someone who didn't know if he'd ever see his brother again, and he had been holding back tears for the entire night both from being so afraid and so determined to get Mario back. Seeing Luigi shake and just quietly sob for that brief moment at the sight of Mario being safe again, then being able to feel it turn into a genuine laugh might be one of the sincerest displays of emotion Charles Martinet has ever brought to his character, and it can be hard not to smile or cry alongside him.
- After King Boo's defeat, Mario stops moving inside of his portrait, and Professor E. Gadd reveals that he just fell asleep out of relief that Luigi did it. Mario truly believed that Luigi would come to save him.
- A Visual Gag: the ballroom dancer ghosts have the same heart. They share a heart!
- Cheering up the various crying Toads throughout the mansion. The uplifting little jingle that plays when they turn the lights on for you helps as well.Toad: Thanks, Luigi! You made my dark and stormy night!
- After fighting bosses like Chauncey or Bogmire, the music which plays in the room
has a strangely comforting effect. - King Boo of all people gets one. When speaking to Luigi right before his fight, he calls his fellow Boos his "friends". Not minions. Not allies. Friends.
- Madame Clairvoya's final conversation with Luigi. Amidst a mansion that is filled with Portrait ghosts who are all either vain, self-centered, greedy, or some combination thereof, she's the only one who is nice to Luigi at all and even helps him try to find Mario. She even volunteers herself to be caught for Luigi as opposed to living an eternal repetitive half-life, unlike the others who are happy to do the same basic activity they did in life over and over again.
- Playing the instruments in the Conservatory and hearing the Super Mario Bros. theme is pure nostalgia fuel!
- Even though it turned out to be a trap from King Boo, Mario still wanted to be happy for Luigi in winning a mansion. It shows just how close the brothers are and how they are always there for each no matter what. Luigi shows this as he may be scared out of his wits by the mansion but he never intends to abandon his brother.
- Scanning the Luigi amiibo in the 3DS remake will grant Luigi a Gold Bone that he keeps until the player turns off the game or if he uses it up upon dying. Much like Dark Moon, using it up will play a small cutscene where Polterpup appears to revive the green plumber with some licks to the cheek. The adorable Polterpup antics and the difference in music composition between the two games makes this an especially relieving Mood Whiplash.
