Sonic CD is now free-to-play on the app store, which is great if you don’t have the game already. The one downside is, it is filled with ads. On pause screens, menu selection, they’re everywhere. Also, you have to have internet to even start the game. You won’t get any ads if you purchased the game before the game went free. You can also pay $1.99 cents to remove them entirely. This is a great opportunity to play one of Sonic’s older adventures, even with added features.