Super Mario Bros. is a strange movie. The very concept is bizarre and
outlandish, and does not seem like something a sensible film writer would create
while in a sane state of mind - the content is variable enough for its intended
audience to be hard to grasp, and roping in so many big-name actors for very
kooky roles can only be described as bizarre.
Of course, it's a strange movie based off a strange video game. With flying turtles, evil walking mushrooms, red blobs that shoot bullets from their masks, soaring pirate ships and many other implacable inclusions, one would think basing a movie directly off the game would be enough, but the wild changes they made just made it even stranger.
I've never heard why the movie was made. I have heard plenty about its production, how it was originally said to be an animated feature before it was changed to live-action, the numerous script changes, the problematic directors, the joyless experiences from the leading actors - but I have heard nothing official about why it was made. Nintendo were doing pretty well in the early 90s; the NES was a success and the SNES was fighting strongly with SEGA's rival console, there had already been some fairly successful cartoons based off their two main franchises, as well as a few comics in Nintendo power. SEGA had also made cartoons and comics of its new blue mascot, so I guess simply to one-up their opponent, Nintendo decided, "hey, you know what we need? A movie with a hugeass budget and Dennis Hopper with a weird friggin' haircut."
I don't know why they needed both.
Judging from the early scripts and changes, it seems it was intended to be a light-hearted affair similar in tone to the games, with fantasy elements filling in whatever the game couldn't provide, only for that to be ditched in favour of a dark and edgy sci-fi realm of parallel dimensions, evolved reptiles and rampant fungi. Given how the games are fairly light on modern technology (conveyor belts and elevators seem to grow naturally in the wild), this is just a little bit odd, to blurt out a serious understatement.
You'd be hard pressed to play the games, then look at the movie and see any immediate correlation between the two besides names, making one wonder how on earth they actually got the idea from four games worth of side-scrolling platformers. Then again, you'd also wonder how they got such a completely ridiculous story and setting without basing it on a video game, despite mangling everything in the process. It's a conundrum!
Despite all that, it adds a certain charm to the film. The vast differences from the source material plus the unique creations are interesting, yet it's a combination of that and the scant few connections to the original that add a level of intrigue to it. We're not beaten over the head with references like, "oh, those small, squat, rounded things that shoot bullets from their gas masks are Snifits!" but rather, "oh, that garbage man who is not small, squat or rounded wearing a gas mask but has no offensive capabilities or does anything of actual use is a Snifit, and we can only tell this because it's wearing a gas mask!" Okay, that's a completely pathetic way to explain what gives the movie its odd appeal, but it's hard to describe without being a complete Nintendo nerd and having watched the movie dozens of times as an impressionable youth.
If you liked Bob Hoskins' accent in Who Framed Roger Rabbit, you'll love this. I'll leave it at that.