Dumb question here. How is 10 on the older games that came out back in the day of windows 98. IE command and conquer stuff? Win 7 seems to run the older games pretty seamlessly.
All I use Windows 10 for is gaming, but I haven't tried any really old games yet.  If necessary, Win. 10 still has the
compatibility settings, just like Win. 7.
The oldest games I've played so far are, Mafia I and Mass Effect I.
No issues with either.
Win. 10 does offer Direct X12, which Win. 7 does not.  Some games are starting to utilize DX12.  Here's a short list from the Wiki.  
DX12 Game ListCoogan