Why wont my game apps work properly?

I just recently got an ipod touch 5th gen, i updated it to the IOS 8.1.2, and i downloaded some games on it such as, Geo defense and Dungeon Defenders. They both did not properly work. Some other ones as well didn't really work properly. Geo defense would just have a black screen but you can hear the sound. The other game wont stop showing the loading page. I dont know if its the apps themselves or my ipod. But recently the ipod itself has had some problems, battery problems and the front screen getting overly hot. I've uninstalled the apps and installed them back and they still did the same thing.

Does anyone know a solution to this problem? Is it the apps or is it my ipod that's seriously jacked up? If you have any advice or answers please tell me, thank you.