This isn't finished, and never will be. BETTER ENGINE HERE - https://scratch.mit.edu/projects/915860102/ Act 1 - Shortly after destroying Robotnik's final defense against him, Sonic is forced to flee Scrap Brain zone as it begins to explode. Act 2 - After falling down a chasm, Sonic finds himself standing in front of a fire wall, Sonic must outrun it Act 3 - Sonic is near the exit, and he to runs through Scrap Brain whilst it crumbles beneath his feet. (Think Terminal Velocity Act 2)
This isn't finished, and never will be. @magar12345 for the original idea