Game that’s old enough to need an update if it would have to be released today, what changes would need to be done to it in order to bring it up to modern day standards from all points of view, while retaining the original’s intentions and spirit?

Firstly, I guess it would be a good idea to update textures and such so it can run at the correct resolution. Also, any compatibility issues caused by modern hardware/software drivers would need to be patched. They're the 2 things that came into my head. Why do you ask (If you don't mind me asking)?

some test i got

Sound cards was what I was thinking of. Not sure how DirectX handles something like Sound Blaster support.

And five minutes with google and still not sure.