“Improved application backwards compatibility for Windows Phone 8.1 Silverlight applications.”
It seems those changes has allowed some games which did not even work on Windows Phone 8 to now come back to Windows 10 Mobile.
On Reddit Fannybeard found some long abandoned apps which did not make the compatibility jump to Windows Phone 8 are now available to download on his Lumia 950.
The list of games include:
Of course perfect comparability can not be guaranteed but if you are nostalgic for some old time wasters now would be a good time to search your old library.