>>713433003

Sonic the Hedgehog 1 on the Genesis was released in the North American market first before any of the other regions. Sega of America really needed it to be released a few weeks before the North American launch of the Super Nintendo and Super Mario World. The EU and JP releases were much more polished overall and have more parallax in some stages and have a few more additional effects.

https://youtu.be/OHE94oBDVW0

https://youtu.be/mK0OFsWWzu4