I'm not too big on nostalgia, but Mario has been in the background for pretty much my entire life, so I was willing to make an exception and go along with it. Even for nostalgia fodder, this was pretty terrible though. What I got from this film is an American reimagination of the Mario franchise, complete with a deplorable 80s pop soundtrack. My brain just melted when I heard ELO, a-ha, and AC/DC blaring through the speakers.
The plot is negligible, but that was to be expected. Mario is transported from Brooklyn to the Mushroom Kingdom, Bowser is on his way to make the princess marry him. Mario and the princess team up to find Luigi (who got lost along the way) and to protect her Kingdom from an evil turtle invasion.
There are some familiar tunes, and a bunch of very basic IP references (tanuki & cat suit, power-ups, and the like), but you don't have to be a big franchise fan to recognize them. The only thing that gave me slight chills was the Kid Icarus bit, not even a Mario reference. They're also very lazy, in that they are just there, plain and simple, nothing about the references was handled with wit or creativity. I hated the Americanized/Illumination treatment, was disappointed they didn't do more with the art style, and disliked the loud/shouty nature of the film. This was just a US CG animation, only with some Mario memorabilia thrown in for good measure. Yuck.