HaxeFlixel is an open source 2D game framework written in the Haxe language, created as a cross platform successor to Flixel, the library that powered many Flash era indie games. Developers can publish the same project to web, desktop and mobile, and the intro sting became associated with that flexible, community driven workflow. As thousands of small jam games and prototypes used the engine, players began recognising its opening sound before menus even appeared. It remains popular as a nostalgic marker of indie development and browser gaming culture.