It wont start!

I just bought this app, and I decided to update it, so I havent even played it yet. When it finished downloading, I tapped on it, the screen turned black for a split second, then immediately went to the home screen. I use a 4G iPod touch, and the application doesnt even appear in my multitasking section! Im not changing my review until this problem is solved!

Obi-wan-mason about GHOSTS'N GOBLINS GOLD KNIGHTS II