Most backwards compatible Xbox games won't support achievements or widescreen TVs
While original Xbox games are getting backwards compatibility, modern features like achievements and widescreen resolutions are likely out.
Phil Spencer's announcement that the Xbox One would include backwards compatibility support for original Xbox games is great news, no doubt about it. That said, certain caveats are starting to present themselves. Specifically, features like achievements and widescreen support simply won't be available because of reliance on the original code for each game.
"Most OGXbox games didn't have [widescreen]," Spencer said when the question came up on Twitter. "Can't really easily change the frame buffer aspect ratio on a shipped game from [backwards compatibility]."
"We run the OG code, so the game will support what the original game supported,' he stated in a later tweet. Players shouldn't expect new Xbox Live achievements either, since doing so would only be possible by patching every single classic game.
It's certainly disappointing, especially after being told the service will support fewer games than Xbox 360 titles. The good news is Microsoft is considering other features, like the ability to run a separate Live login for classic Xbox games. But until backwards compatibility is live, you should probably assume that the experience should only reflect what you had on the original consoles, screen layout and all.
Currently, Crimson Skies and Fuzion Frenzy are the only Xbox games with confirmed backwards compatibility support.