Mushroom Kingdom Fusion

Mushroom Kingdom Fusion is an unofficial fan game crossover with many different series and characters, such as Mario, Zelda, Mega Man, Metal Slug, and many others. It is a side-scroller platformer with a dark tone.

Someone called "The Fusionist" is fusing all the gaming worlds together. The Mushroom Kingdom Coalition, formed by heroes from across the gaming dimensions, have come together to stop him! They must gather the 9 World Keys and confront him before it's too late!