Sonic Mega Collection Plus
To your first question, officially, SEGA authorized the emulation of his games so yes you can play legally. To your second question no sorry i don't have this game but i know where can you find it at normal speed.
a friend just found this and I'm extremely confused. I have ZERO recollection of this post, and I don't remember deleting it. I'm so confused lmfao. I'm... sorry for the stupidity???