Play original xbox games on the xbox one s?

Hi

If games from the very first Xbox are compatible with the xbox 360, do they also run on the xbox one s?

Xbox One (S / X) can play both Xbox 360 and XBOX games.

That means if they work on the xbox360 does it work 100% on the xbox one s?

Not all games are backward compatible. There's a list of compatible games that is updated regularly, but I have no idea where to find them right now.

Not every game works, here the Xbox 360 hardware is emulated, simply explained, the Xbox One completely mimics the hardware of the Xbox 360 via software. Most games work and run smoothly