Progressive Scan for Sonic 2 & Combat Cars?
Does the Genesis core provide a progressive mode option for interlacing?
I know emulators going back to Kega Fusion did this and it looks really good on modern displays.
This is preferable as it gets rid of the visually annoying combing artifacts that plagues modern displays and shows odd and even lines together.
It would probably help for 5x scaling too.
Example below:
Genesis Plus GX supports this too.