The original Bumper Engine is today as strong as ever. With a great number of fan developers trying their hand at it, modifying it and building levels to learn about and test their own design ideas for Sonic.

From the trailer video description:

"The Bumper Engine is a Unity-based 3D Sonic development kit for users to develop their very own Sonic the Hedgehog levels and environments. Built on top of LakeFeperd's HedgePhysics, This SDK includes many built-in assets for users to easily drag, drop, scale and rotate in order to piece together their own unique level designs, even if you're new to the Unity platform."