The 2013 Retro Engine remasters of Sonic the Hedgehog and Sonic the Hedgehog 2 have been updated, and if you have an Apple App Store account and download either of these games on your iOS device, they will now be free of in app purchases and ads. The android versions from the Google Play Store have not yet been updated, but you can keep an eye on them for a similar update in the near future. Here are the links to the games:

Sonic the Hedgehog Classic (2013 Retro Engine remaster) – apps.apple.com/ca/app/sonic-the-hedgehog-classic/id316025912

Sonic the Hedgehog 2 Classic (2013 Retro Engine remaster) – apps.apple.com/ca/app/sonic-the-hedgehog-2-classic/id347411942

Sonic the Hedgehog Classic (2013 Retro Engine remaster) – https://play.google.com/store/apps/details?id=com.sega.sonic1px

Sonic the Hedgehog 2 Classic (2013 Retro Engine remaster) – https://play.google.com/store/apps/details?id=com.sega.sonic2.runner