https://wiki.dolphin-emu.org/index.php?title=Sonic_Mega_Collection
"Problems
Frame Issues
When the game lags, it is possible that it will duplicate or show the wrong frames in the wrong order. This is most evident in Blue Sphere; where it will happen when there are any number of spheres on the screen. In order to avoid this, enable "Emulated CPU Clock Override" and set it to 150% or higher."
"Problems
Frame Issues
When the game lags, it is possible that it will duplicate or show the wrong frames in the wrong order. This is most evident in Blue Sphere; where it will happen when there are any number of spheres on the screen. In order to avoid this, enable "Emulated CPU Clock Override" and set it to 150% or higher."