Project M originally began as a mod for Super Smash Bros. Brawl to revert Falco's moveset to how it was in the previous game Super Smash Bros. Melee before the project significantly expanded its scope. Falco's moveset in the former game contained many distinctive attacks considered unwelcome to competitive players, while his moveset in the latter game had the exact same moves as Fox, but with different statistics and properties.

While the Project M Backroom was preparing the release for Project M Demo 2.5, a mod of Brawl that makes it play like Melee, they discovered that there was a bug in the game where button inputs can take anywhere between zero to two frames before being recognized by the game. This means that anytime you press any button in Super Smash Bros. Brawl, the attack might start up later. It is unknown why this happens.