This app has some known problems. Lots of crashes, battery drain, flickering, app turns on then off immediately, etc. I suggest waiting until the next update to the app.
P.S. It has similar problems in the Android realm, as well.
An update came out today before my post. It did not fix the battery drain issues. I emailed the games with friends people, asking them for a fix. It is hard to complain alot for a $2.99 app, but the drainage rate is off the scale! I was under the impression that Apple will not approve an app if it drains the battery too much.