iPhone keeps on getting "stuck" on apps.

When I tend to play a minor app, (Super Hexagon, Dumb Ways to Die, etc...) my phone wont let me exit it. I will try to turn it off, press the home button, nothing happens! I even have the assistive touch to use it for this kind of issues, it does not help! I do not know if this happens on other iDevices running IOS 7 but it is very annoying, considering how "great", the 5s is supposed to be.

Plus, my phone gets smoking hot! I really do not understand why!