The existence of the very project itself. What began as an attempt at a fighting game based on the series turned (after a badly-timed cease and desist order from Hasbro) into a brand new quadruped-fighter game with a brony sensibility, character designs from Lauren Faust, and the Skullgirls engine.
Nappy (one of the members of Mane6) vs. Hirosasshi prior to the Canterlot Gardens tournament, playing Twilight and Applejack respectively. Though Nappy was the overall winner, the match ended with the game's very first double-KO.
alpaca21 managing to get all the way to the finals (and put up a really good fight) using Rainbow Dash; an unfinished character lacking any Supers who was only just revealed at the CLG event, meaning he would have had no opportunity whatsoever to practice with her, or any idea of how she worked at all until he started playing. And he still managed to pull of some very nice combos, and even get one Perfect win, against a fully playable character with Supers. The devs gave him props for that.
Hirosashii, who was the winner of the tournament, defeated alpaca in the final round with a perfect using Applejack.
It has been announced that the game has been nominated for EVO 2013. The game whose community donates the most money to the Breast Cancer Research Foundation will be featured at the event.
And then the bronies donated so much money, the EVO organisers had to change the rules to accomodate for it.
Less awesome since it's very likely that this was why Hasbro sent the C&D order.
Now the game's engine will be switched from Fighter Maker 2000 to the Skullgirls engine due to that game's Indiegogo campaign raising $725,000 USD. Sure Mane6 have to start from scratch, but the Z Engine completely blows Fighter Maker 2000 straight out of the water in terms of what can be done and is far easier to work with. This means that out of the ashes of Fighting Is Magic, a new grander game will emerge. It proves that creativity and passion for a work can triumph in the face of C&Ds.