Arrow keys to move, z to jump, down while running to spin. Press z while ducking do do a spin charge. (You have to keep on pressing 'z' like in the old games. Pressing it once won't get you very far!) Run into the bouncers to bounce. Press p to change level.
Thanks to @MrLog for the original project for me to remix. Guess what? Scratch 3 blurred the levels, making them all look blocky and bitmap-y. Why do tech companies INSIST on blurring everything you enlarge?! Just ENLARGE THE PIXELS!!! They also completely broke it! I added 3 new levels, a brake and spring sounds from the mega drive games, and you can now see where Sonic is. The same noticeable bugs are those on the original version. § UPDATE LOG § 14/07/2018: red bouncer now functions added orange level