Read this before you play.
When you finish the game or die I mean lose the game, it might just froze because the game doesn't know what to do so, yeah you're pretty much stuck on a black screen.
If you do encounter this which you would definitely will, just close the game using your task manager and find the application that says ue4. Just end task it. If you don't know how to open you task manager : ctrl + shift + esc = opens task manager.