This is Sonic 2 from the Sega Saturn compilation disc Sonic Jam. I read that these were completely re-programmed for the Sega Saturn.
This version is pretty good, but it does seem a little glitchy at times and the music doesn’t seem to have the same quality it did on the Genesis. There were plenty of times when Sonic controlled strangely or the physics of the game go a little haywire.
Sega added some new difficulty modes that add to the replay value but other than that it’s Sonic 2, you can’t go wrong.