"...upgrading will mean saying goodbye to Windows Media Center, the card game Hearts, and Windows 7's desktop gadgets... watching DVDs will also require 'separate playback software'...
Microsoft has also changed how updates will work with Windows 10. Although the Pro and Enterprise editions will both be able to defer updates, Windows 10 Home users will not have the option. Updates will instead be downloaded and installed automatically as soon as they're available."
http://www.theverge.com/2015/6/1/8696949/windows-10-feature-loss
I suspect someone will figure out how to import W7 games into W10, just as you can do now with W8.x.
http://www.intowindows.com/play-windows-7-games-in-windows-8/
6 Features Disappearing in Windows 10 (and How to Replace Them)
http://www.pcmag.com/article2/0,2817,2485170,00.asp