In 2010, a fan-made game called Super Mario Bros. Crossover was released, which let players tackle the Nintendo classic using not just the standard plumber, but a cast of characters from other 8-bit games as well.
It now has a sequel which is kicking things up a notch, taking the 8-bit visuals from the first and running right into Super Nintendo land. With a few detours in...Game Boy land?
The game will be available in the next month or two, and when it is, it'll be playable at the link below.
Super Mario Bros. Crossover [Exploding Rabbit]