I had this idea for the final world being the secret sonic level in the original game for a long time. This is being a distorted & slowed version of Hill act 1.Gym (Reversed ... theme) to signify you're facing off the exe you first encountered years ago. This would've been pretty cool as the background for the finale of USEM. (Although Idk about the epilepsy part)
Since I have my surgery on July, I won't be able to listen to music temporarily, So any music that wasn't finished before is going to be transferred to different composers.