Mushroom Kingdom Fusion (MKF) is an expansive, non-profit crossover fan game that has been a staple of the fan-gaming community for nearly two decades. Combining the classic platforming of Super Mario Bros. with a massive multiverse of characters, weapons, and worlds, it is widely considered one of the most ambitious fan projects ever created.
Development and History
The project’s journey began on December 27, 2007, founded by a developer known as JudgeSpear. Originally titled Super Mario Fusion: Mushroom Kingdom Hearts, the game was built on a modified Hello Engine. It quickly gained internet fame, receiving coverage from major gaming outlets like Kotaku and Destructoid.
Over the years, the project transitioned through several eras:
- The Original Era (2007–2013): The project grew from a solo endeavor into a collaborative effort by the Fusion Development Team. This era saw the introduction of a wide variety of non-Nintendo characters.
- The Revival Era (2018 – Present): After a hiatus, development was resumed by D-TurboKiller and later led by dooki51. This modern phase focused on optimizing the engine and adding high-fidelity content. As of January 2026, the game has reached version v0.93, introducing new levels, cutscenes, and character unlocks.
Gameplay Mechanics
MKF is a 2D side-scrolling platformer that blends traditional Mario physics with “Run and Gun” elements. While the core movement is familiar to fans of Super Mario Bros. 3, the gameplay is significantly altered by unique character systems.
Key Features:
- Unique Playstyles: Every character possesses distinct movement physics, health systems (such as Link’s hearts or Mega Man’s health bar), and specialized abilities.
- The Weapon System: A defining trait of MKF is the ability to use firearms and projectiles from various franchises, including Halo, Doom, Metal Slug, and Contra.
- Fusion Suits: Characters can find specialized power-ups that transform them into “Fusion” versions of themselves, such as Mario donning Spartan Armor, Wario becoming a Duke Nukem variant or Luigi becoming Guile from Street Fighter, while chucking out those sonic booms.
Characters and Worlds
The game features a roster of over 21 playable characters and spans more than 200 levels across 9 massive worlds.
| Character | Origin Franchise | Notable Mechanic |
| Mario & Luigi | Super Mario | Traditional power-ups and specialized Fusion Suits. |
| Sonic & Tails | Sonic the Hedgehog | Momentum-based speed and spin-dash capabilities. |
| Mega Man & Roll | Mega Man | Charge shots and Robot Master weapon systems. |
| Link | The Legend of Zelda | Sword combat, shields, and item-based progression. |
| Samus Aran | Metroid | Missile systems and the iconic Morph Ball. |
| Simon Belmont | Castlevania | Sub-weapons and classic whip combat. |
| Ryu Hayabusa | Ninja Gaiden | High-speed agility and wall-climbing. |
The worlds themselves are diverse, ranging from traditional Mushroom Kingdom landscapes to environments inspired by Halo, Mega Man, and Castlevania. The narrative follows the Mushroom Kingdom Coalition as they attempt to stop a mysterious entity known as “The Fusionist” from merging all gaming dimensions into a single reality.
Modern Improvements
In its current state, the Fusion Team has significantly enhanced the technical foundation of the game. Recent updates have implemented:
- Built-in Gamepad Support: Seamless integration for modern controllers.
- Visual Support: Compatibility with modern displays and resolutions.
- Expanded Content: New bosses, revamped world maps (especially World 8), and additional secret characters like Firebrand and Meta Knight.
Mushroom Kingdom Fusion remains a monumental achievement in the fan-game scene, acting as a playable museum of gaming history.
Grab the latest version from the projects itchio page.