I know there is a difference in APIs from Windows 8 to Windows 10 that is what makes a game to work from system to system and for that to happen it implies coding with the different APIs and you just can't have some Windows 10 dll on Windows 8 , if the coding done uses the different ddl that you just can't have on Windows 8 then the game does not work anymore on Windows 8 and it will just Work for Windows 10 .
It needs coding also for Windows 8.