Should SNK hire Code Mystics to update the Metal Slug 3 and the rest of the series on GOG & Stea,? They did update Garou: Mark of the Wolves from DotEmu, i asked them on twitter and this was their response:

"We'd love to, but that's not our call. SNK brought us in to replace DotEmu's Garou due to overwhelming fan demand. Presumably they'd need to see same sort of demand for a replacement of Metal Slug 3 to do the same thing there."

They already ported MS 3 for PS4,PS3 and PS Vita and it is superior version compared to the GOG and Steam.