- Fan Nickname: Due to the game taking place in a hotel, many fans immediately started calling it Hotel Mario 2 and Hotel Luigi.
- I Knew It!: Luigi had a different looking Poltergust with a new plunger shooting capability in Super Smash Bros. Ultimate. However, none of the Smash gameplay at the time before Luigi's Mansion 3's announcement showed him grabbing anybody, using his new tether ability, or performing his Final Smash (all of which involve his Poltergust). Viewers did get to see the new Poltergust in the animation created for Smash's trailer revealing Simon and Richter, leading to theories that there would be a new game in the series. They were right.
- Meaningful Release Date: The game was released on Halloween, in keeping with the horror theme. Interestingly enough, this is actually a departure from Nintendos standard release schedule, with October 31st, 2019 being a Thursday — most Nintendo-published games release on Friday.
- Moved to the Next Console: The game was initially conceived for the Wii U, with its various concepts being tested in prototypes running on the console.
- Name's the Same:
- Morty shares his name with a Pokémon Gym Leader who specializes in Ghost types. It's almost guaranteed their names are both based on the association with the root "mort" and "death". Additionally, he shares his name with the certain grandson of a deranged scientist.
- This is not the only game with a hotel called "The Last Resort".
- Permanent Placeholder: The title. It was a working title when the game was announced during the 2018 Direct, but later kept as the game's official title.
- What Could Have Been: It was mentioned during the 2019 Treehouse Live that the setting for the game was originally going to be at something like Hollywood, but it was changed out of fear the levels would get to be repetitive. Morty's movie studio is a leftover from this.
Trivia / Luigi's Mansion 3