Sonic CD is out on Xbox Live Arcade, iOS, and Android! I bought the Xbox version, it's very well done. Had to switch the soundtrack to the US version, though — the intro just isn't the same without the SONIC BOOM song! You can unlock Tails too, which should be interesting. They also changed the spin-dash controls to be more like Sonic 2 (and newer) where you tap the button over and over to increase speed instead of holding it, though there's an option to switch it back to the original mode too.