DISCLAIMER: I DID NOT MAKE THE ENGINE. THIS TOOK SOOOOOO LOOONNNNGGGG. I was like "Hey, It would be cool to make a remix and make this this hidden palace from Sonic 2", but this ended up taking at least 6 hours of constant work to complete, so fskdjfbaoesf. Oh yeah, Z to jump, Arrow keys to gu fest, and down + z to charge a spin dash. (You have to keep pressing it like in the classic games)
The music is from Sonic Adventure 2's "Sky Rail". HUGE credit to @tomicool for the engine, and @sonicjeremy for the sonic sprite.