Sonic the Hedgehog 1 is release back in 1991 and it is remastered, originally released with Sega Genesis ROM port to iOS, now replaced with remastered.
iOS https://apps.apple.com/au/app/sonic-the-hedgehog-classic/id316050001
Android (Google Play): https://play.google.com/store/apps/details?id=com.sega.sonic1px&hl=en_AU&gl=US
Android (Amazon Appstore): https://www.amazon.com.au/Sega-of-America-Sonic-Hedgehog/dp/B00D74DVKM
Windows, Windows UWP, Linux, Mac, Vita, Switch, Web, and other platforms: https://github.com/Rubberduckycooly/Sonic-1-2-2013-Decompilation