Q: Why does My iPad suddenly close games when I am playing

It may be a bug in the game. You should check for updates. Is it still running in the app chooser when you double click on the Home button? If it's not then it really crashed badly.

So it's just losing the focus. Probably needs to be updated for iOS 10. The maker may not have done this yet. You can see the version history in the app store.

Same here & not just with games but apps. Deleting & reinstalling them usually works or a hard reset (power & home button) but sometimes it'll happen again.