I am putting in backwards compatible games that are on the list... Says "Game isn't...

The Xbox One X can play all Xbox One games, all backwards compatible Xbox 360 games and all backwards compatible Xbox (Original Xbox) games. Here is a list of all the

backwards compatible games, more are being added to, so don't be put off if your favourites aren't listed just yet.

The 1 and only game I want on that list isn't there

The Xbox One X can play all Xbox One games, all backwards compatible Xbox 360 games and all backwards compatible Xbox (Original Xbox) games. Here is a list of all the

backwards compatible games, more are being added to, so don't be put off if your favourites aren't listed just yet.

The 1 and only game I want on that list isn't there

Which is?

Just put the game in. If it's backward compatible then it'll play, if not the console will just tell you that the game isn't backward compatible.

It probably isn't backwards compatible then. The list Microsoft released isn't accurate. Games were put on, broken half way through, and then taken off when the errors were noticed. They didn't bother to update the list. There are a few games that aren't
on the list and that work, and games that are on the list and don't work.

SNK vs Capcom isn't backward compatible. There's a list of all the backward compatible games and the regions they're backward compatible in on Wikipedia for future reference.