Three years ago, a group of enterprising Nintendo fans launched Project M, a mod for the 2008 Wii game Super Smash Bros. Brawl. The group's mission statement: Brawl was a terribly flawed game that needed fixing, and through mods they could mend it.

That mission has been accomplished. Project M says version 3.0 of the mod, released today, transforms Brawl into a game worthy of the serious tournament play its predecessor Super Smash Bros. Melee still enjoys.

Nintendo released Melee on GameCube in 2001. The four-player fighting game with an all-star cast of Nintendo characters quickly developed a hardcore competitive fan following. But Nintendo thought the game was "too difficult" and changed things up for the Wii version of the series, Super Smash Bros. Brawl. This might have made things easier for newbies, but it alienated hardcore players.

"Super Smash Brothers Brawl was made to appeal to newcomers somewhat at the expense of some of the series' most dedicated fans," says Project M senior developer Corey Archer.

But the newer game did have its appeal, since it expanded the character roster from 26 to 37, adding more fan favorite competitors like Pit from Kid Icarus, Solid Snake and Sonic the Hedgehog. Project M's goal was to overhaul the move sets of every one of those characters and bring back characters that were not carried over from the GameCube.

Any Wii or Wii U owner with a copy of Brawl can install Project M simply by downloading the mod to an SD card and inserting it into their console, no hardware hacks or coding required. The group says about 100,000 users have downloaded and installed previous versions of the mod.

"Brawl has a memory exploit in its Stage Builder that allows us to dump an executable on the stack and run it," says Archer. "We use this exploit to load a code handler, which loads our codebase and assembly hooks into memory when booting the game."

From there, Project M can make Brawl use assets it created – custom stages, new character models, animations, anything. More than 100 contributors from around the world have worked on Project M over the years, with a select group of senior members forming a leadership council that has made decisions about where to take the mod.

Project M's makers say they want their version of the game to be accessible to newcomers, but Brawl will only have lasting appeal if it offers players an environment where they can continuously improve, constantly pushing each other to new levels of competition. This requires that every playable character in the game is more balanced against one another. Project M says accomplishing that in a game with as many characters as Super Smash Bros. is a nightmare.

Nintendo itself didn't even come close; Archer says that in high-level Melee play, the adorable Pokemon character Jigglypuff and Star Fox's Fox McCloud were dominant. In Brawl, it was Metaknight from the Kirby series who could ruin any other character.

Much of the past four years has been spent addressing this issue, and Project M believes it's finally put everyone on something of an even playing field.

The established Smash Bros. tournament scene will have to get a crack at version 3.0 to determine whether or not Project M has been fully successful at balancing the roster, and that will take time.

As big Nintendo fans, the Project M team hasn't just used their access to the Brawl code to tweak the gameplay mechanics. They've had some fun, too. Sonic the Hedgehog's homing attack now includes classic animations from the Sonic Adventure series as an homage for fans. Diddy Kong has been given a taunt move in which he pulls out juggling balls, a reference to the Donkey Kong Country games.

Archer says that after 3.0 there will likely be only one more major release with a few more tweaks before his team considers the project finished for good. It might add even more Nintendo characters to the mix, he says. "If we come up with any good ideas for the remaining unused character slots we will probably be filling at least a few of those up as well."

Then maybe they can work on figuring out how to crack Nintendo's upcoming Smash Bros. for the Wii U.