Fandom Life Cycle: Stage 5, because the Mario series is basically the most well known, popular video game series in history. Especially true of the 'Mario Mania' years, where Mario was more well known to American children than Mickey Mouse.
Word of Dante: Several games have had single Magikoopa characters/enemies which were nameless or seemingly generic, but the fandom has universally decided that they are all Kamek. Some examples include the Magikoopa who was going to be in Mario Kart 64 but was replaced with Donkey Kong; the Magikoopa who blasts Mario away from Peach's Castle in Super Mario Galaxy (a trading card for SMG confirms that it was indeed Kamek); the Magikoopa who aids Bowser in Mario & Luigi: Bowser's Inside Story; and the Magikoopa who was a boss in Yoshis Safari. Two games, Super Mario RPG and Super Princess Peach, do have Kamek in them, but he was unnamed or misnamed in the English versions. Bizarrely, Mario Party DS has him named Kamek, but in Mario Party 9 (where he's playable), he is misnamed "Magikoopa" in the North American version... but not the European version.
However, the Magikoopa enemies are named "Kamekku" in Japanese, which could be romanised as "Kamek". So in a way, they ARE all Kamek(s). This is probably also why Kamek's name was changed to "Magikoopa" in Mario Party 9, as the localisers may have mistaken "Kamek" for the species name rather than the character name.
In the original 90s castillian spanish dub (not the re-dub done in 2010 by Kidsco), a lot of characters were voiced by people that worked in The Simpsons and would later work in Futurama. Mario was voiced by Angel Egido, which did grandpa Simpson for the first 11 seasons before retiring. Hip and Hop were Isacha Mengíbar (Lisa) and Sara Vivas (Bart) respectively. And Luigi was voiced by José Padilla, who provided (and, as of 2013, still does) the voices of Seymour Skinner in The Simpsons, and Zapp Branigann and Zoidberg in Futurama.
Deleted Scene: Nearly 30 minutes of footage was cut to get the movie down to a proper running time. Deleted scenes include:
An extended sequence of Koopa chasing Daisy's mother in New York, which featured him gazing admiringly at the buildings which would later inspire his warped construction projects in Dinohattan.
Mario and Luigi actually confronting the "Scarpelli Bros.", Mike and Doug, in the River Front Cafe. They threaten the cafe's owner, Pascal, by using their bosses' name. Pascal takes Mario aside and offers him and Luigi a free lunch to make it up to them, which leads to:
An alternate scene of Mario and Luigi eating. Daisy enters the cafe and uses the payphone inside, slipping on a wet floor as she leaves. Luigi catches her and the movie continues that way.
Mario and Luigi getting ready for their dinner date, during which Luigi expresses embarrassment at being a plumber. Mario chastises him and tells him he has no "family pride."
An extended sequence in the de-evolution chamber, during which one of the devo technicians is de-evolved into slime. A puddle can still be seen on the floor in the final film.
Iggy and Spike get drunk at the Boom Boom Bar and rap, which is referenced later by Lena as them "preaching your overthrow."
Various assorted scenes, including additional sequences from the cut "family pride" subplot.
Enforced Method Acting: Mojo Nixon, who played Toad, was legitimately terrified of Dennis Hopper's performance as Koopa, particularly the scene where he was de-evolving and strapped to the chair.
Executive Meddling: The script by writers Dick Clement and Ian la Frenais was so sophisticated and intelligent that it inspired Bob Hoskins, Dennis Hopper and Fiona Shaw to sign onto the project. However, the producers feared it wasn't kid-friendly enough, so they forced heavy re-writes and barred directors Rocky and Annabel from contributing to them.
Further changes to the script in terms of special effects and character-development severely limited their vision even further.
In the end, over 20 minutes of footage was cut to get Mario and Luigi into the parallel world sooner while the atrocious animated intro was inserted to make up for it.
Fake American: Bob Hoskins does such a good job at playing one that between this movie and Who Framed Roger Rabbit, many American kids were genuinely surprised to discover that he's actually British.
Old Shame: John Leguizamo's film debut. His next film, To Wong Foo, Thanks For Everything, Julie Newmar earned him a Golden Globe nomination for Best Supporting Actor. Bob Hoskins and Dennis Hopper regret it as well, though they were both well into their careers.
Conversely, many of the non-leads have stated it was one of their favorite movies to work on. Some even say it is their favorite movie.
Troubled Production: As Dennis Hopper put it, "It was a nightmare, very honestly, that movie. It was a husband-and-wife directing team who were both control freaks and wouldn't talk before they made decisions. Anyway, I was supposed to go down there for five weeks, and I was there for 17. It was so over budget.""
An early draft of the script shows that Bowser only disguises himself as a human in his first two scenes, the Princess character is named Hildy and Bowser wants to marry her in attempt to obtain the Crown of Invincibility with which to take over the Mushroom Kingdom. Actual game enemies such as Piranha Plants and Thwomps make appearances, Toad accompanies the Mario Bros. throughout their journey as a main character, a baby dinosaur named Junior thinks Mario is his mother, Luigi gets Raccoon Power at one point, one of Bowser's lackeys (a possible prototype for Kamek) tells Mario "Your Princess Is in Another Castle", Mario and Luigi sing a Villain Song for Bowser, Bowser ends up falling into a pit of lava... In other words, this draft is much more faithful to the games.
According to this issue of TV Guide, the movie was originally planned to be released in 1991 and would have been animated.
Jerry Goldsmith was attached to score the film but pulled out due to scheduling conflicts.
Mario's character was written differently before Bob Hoskins was attached to the role. Screenwriter Parker Bennett described him as "Bill Murray-esque", closer in age to Luigi, and that they had Bruno Kirby in mind for the role.
[...] what we decided is, "Okay, Mario has a big chip on his shoulder about being a plumber. He’s inherited his dad’s business [and] it’s not what he wants to do;" it’s sort of a It's a Wonderful Life thing with Jimmy Stewart at the bank when he wants to be traveling the world.
[...] And in the end he learns through the adventure that he’s the greatest plumber in the world and he needs his brother and they’re a team together and that was sort of what we were trying to do for that.