These Sonic 1 & 2 ports are based upon code reverse engineered by Rubberduckycooly, with the developer behind the port itself being "heyjoeway".
Sonic 1 & 2 for the Switch GitHub release page (download link):
https://github.com/heyjoeway/Sonic-1...ation/releases
Sonic 1 & 2 for the Switch GBATemp release thread (more info):
https://gbatemp.net/threads/sonic-1-...switch.581099/
Sonic 1 & 2 for the Vita GitHub release page (download link):
https://github.com/Xeeynamo/Sonic-1-...ation/releases
Sonic 1 & 2 for the Vita release tweet (more info):
https://twitter.com/xeeynamo/status/1350982045594431488
Source
Sonic 1 & 2 for the Switch GitHub release page (download link):
https://github.com/heyjoeway/Sonic-1...ation/releases
Sonic 1 & 2 for the Switch GBATemp release thread (more info):
https://gbatemp.net/threads/sonic-1-...switch.581099/
Sonic 1 & 2 for the Vita GitHub release page (download link):
https://github.com/Xeeynamo/Sonic-1-...ation/releases
Sonic 1 & 2 for the Vita release tweet (more info):
https://twitter.com/xeeynamo/status/1350982045594431488
Source