The original Sonic has been ported many times, so I’ve taken a look at all the ports. Please note that this only includes ports and not emulated versions in collections.
Sonic the Hedgehog (Mega Drive)
Sonic the Hedgehog (Mega-Tech)
Sonic The Hedgehog (Mega Play)
Sonic the Hedgehog Mobile (Java)
Sonic Mega Collection Plus Mini (Flash Demo of Green Hill Zone)
Sonic the Hedgehog Genesis (GBA)
Sonic the Hedgehog (Retro Engine – Android)
Sega Ages Sonic the Hedgehog (Switch)
Sonic Origins (Xbox One/Series, PlayStation 4/5, Switch, PC)