If you have the old Sonic 1 version, it will be updated to this ad-supported version. Good job Sega. So if you don't want to do with this version, which actually adds nothing, do not update and/or backup your iTunes copy.
And these "Sega Forever" games don't let you save offline unless you buy the ad removal. That's very irritating on its own, and it gets worse: if they ever stop being on the store then re-installing them becomes impossible. We don't need more ways for our games to break, and this is actually built into them. # I'm not supporting this. It can break at the drop of a hat, and not even an app backup or old un-updated device can save it if that happens. (Unless you already have the previous version...) And these include games that were already removed from the store a while ago. That's making me even less confident that they'll stick around, and these versions also have the problem of breaking the ability to install if they vanish. And in this case, I bought a normal full-version app. They're changing the nature of my purchase. This change is completely unacceptable.
Dang it Sega. How can the same company who makes such good decisions like publishing Alien Isolation turn around and make stupid moves like this. Eh. I'm probably done buying Sega mobile crap. I was going to pick up the Sonic games I didn't have eventually, but not anymore. What's the point. I'd rather emulate them at this point.
For the SEGA games you already bought, use Restore Purchases to remove the adds. Sadly, you'll still get some SEGA app adverts, but that's better than the app no longer working, isn't it?
If I remember correctly you need to beat the game to unlock Tails, and beat the game with all Chaos Emeralds to unlock Knuckles.
So this is odd. I have not paid for the ads free update and I never bought the older version but when downloaded this to my Apple TV it doesn't have any ads or any where to buy the ads free. I guess it's just free for Apple TV?
Actually the debug menus and all the cheats still work, they're just triggered differently on the touchscreen. You can read about it here, pretty much works the same way on both Sonic 1 and 2: http://toucharcade.com/2013/05/27/a-guide-to-sonic-the-hedgehog-version-2-0s-hidden-level-select-debug-mode-and-many-more-secrets/
Got this the afternoon in June 1991 following my Biology Regents. Super game, but it's 2017. Haven't there been enough Sonic renditions?