This is the gold standard for the community. While you might not find a file explicitly named "Sonic Bumper Engine" on the front page, the forums are filled with "Open Source" projects.
: Features an intelligent camera system, splines for light dash trails, and Sonic Adventure 2 style ball switches. Evolved Physics : A newer expansion, Bumper Engine V2 sonic bumper engine download
Close this article, open GameMaker, and run that Sonic Bumper Engine. The next great Sonic fangame might just be yours. This is the gold standard for the community
Change 6 to 8 for a faster Sonic. Change to 4 for a slower, exploration-based game. splines for light dash trails
Several projects have used the engine to demonstrate large, open-world Sonic environments.