It's honestly amazing. And with auto enhancements with resolution and HDR.
So is this all emulation and software based? How is Microsoft doing this?
If I had to guess, it actually goes back to how the first Xbox One was engineered.
Remember when news broke that Xbox One was actually running a 3 OS Hyper-Vs in one solution? An OS Hyper-V, a game Hyper-V, and one hyper-V that ties it all together. I'll refer to that one as the Rug. This seemed odd at the time. Why virtualize code that could run natively on the hardware. And I think we now have our answer. It was forward looking at the time, we just didn't realize the implications.
The implications being... MS has already ported the XO's game hyper-V to XSX. That the Xbox hardware is NOT the Xbox platform, rather, the game Hyper-V is the Xbox platform.
XO code does not know that it is running on XO or XSX, it only knows that it's running on the game hyper-V. This is why original code will run un-altered on XSX. The quality of how it will run will be up to the port of the game hyper-V to XSX, but I'm guessing that this is why we can also see crazy enhancements to native code. The game hyper-V gets a request from the game software to render at 1080p, and it's like, "No dawg, I'm gonna render that shit at 4k!"
"Render this in SDR, please. That will be fine."
"F-that! I'm going to ask my ML buddy over here to add HDR!"
Then the game hyper-V passes it over to the Rug to spit it out to your TV with the enhancements. Game code is unaware that any of this is happening.
I surmise this is also the same approach to XOX enhancements to 360 BC titles. The main difference here is that 360 software was never written to run in a game hyper-V, so MS built a custom layer to facilitate that, on a game-by-game basis.
I have more crazy theories about how this applies to Lockhart as well.
XSX code is in the same state as XO code. It hands its instructions off to game hyper-V, but in Lockhart's case, game hyper-V will be like, "Hmm, ok. What if I render this at 1440p instead of 4k? And this raytracing stuff? Let's just not do that at all, if that's OK with you." Essentially, hyper-V is de-hancing games for Lockhart. This could mean there is still only one spec to develop to. Nothing needed by the devs to target both Anaconda and Lockhart. Game hyper-V does all the work. Again, XSX game code is unaware that this is happening.
Anyhow, if you got through that thanks for listening to the ramblings of a madman.