Hello Mario Engine – Anyone can make a Mario game as easy as 1-2-3

Hello Mario Engine (formerly called Hello's Mario Engine, Hello Engine) is a feature-packed, fully-documented, easy-to-use Super Mario game engine for GameMaker: Studio, developed by Hello Fangaming from MFGG (Mario Fan Games Galaxy) in 2007. It enables anyone to make a Mario game with ease. Even better, it's free and open-source (under the new BSD License), which means you can make whatever you want with this engine, without any restrictions.