"Another Super Mario Bros variant loosely based on the Halo videogame."
Few would argue that Super Mario Bros is one of the best-known, loved and popular games of the last decade or so. Many remakes and variants continue to appear, often created by the users themselves. Super Mario Fusion is one of them.
As you might already be starting to work out, Super Mario Fusion, although protagonized by Super Mario (as is logical), is loosely based on the videogame Halo, so the weapons you have are from this game, like a pistol, rifle, plasma gun, and methods to defend yourself like fireballs, hammers, etc.
Although the graphic look of Super Mario Fusion leaves a lot to be desired (above all compared to more modern Mario games) if you are a fan of the ineffable Mario then you'll still love it.