Are these games also playable offline without Internet on Xbox Series X?

State of Decay should work offline, Mass Effect definitely will

nope, most if not all current games on xbox one will be playable on the series x, eventually there will be games release just for the series x and they wont be playable on previouse console versions.

Xbox one s and Xbox one X are the same family, series x will be the new console and eventually (a couple of years down the line hopefully) games will only be release on the series x family so the xbox one x will not be able to play them.

If this is not confusing

Hi Yevhenii. My name is Kyle and I'm an independent advisor.

When purchasing a game make sure you check it's store page, it will clearly state which system the game is for. Sometimes 'Xbox Series X|S' is included in the game title, but if not it will also list 'Xbox Series X|S' under 'Playable on'. If it says Xbox One under Playable on, but not X|S, that means it's an Xbox One game.

Additionally, some games also choose to support Smart Delivery, which ensures you get both versions with your purchase. It is down to the game publisher to support this feature, and some publishers choose to sell a version without Smart Delivery just for Xbox One systems.

You can purchase 'The Crew Motorfest Xbox Series X|S Upgrade Pack' from the Microsoft Store to upgrade your Xbox One license to the Series X version.

Please reach back if you have further questions.

Thanks,
Kyle

when will this come https://www.ign.com/articles/microsoft-xbox-series-x-s-games-playable-xbox-one-cloud-gaming xbox series x games playable on xbox one old gen consoles via cloud gaming feature

If it is an xbox one s or x or og xbox one hw can't play it without his own subscription as starfield is only playable on xbox series consoles or pcs