It's nice, good work. I wonder if you might be better off without the ads though. Not much revenue, and without them you can possibly build a bigger user base as a reputation point for your resume.
The ad made me buy the in-app purchase instantly, even before trying (it's placed nearly in the way of the action button).
So in my case, the ad worked as a immediate trigger to pay.
(I would have bought it a 1€ directly in the store, without any hesitation, too. So it made no difference in the end. I'm just a little annoyed that in the future I might have to restore my purchase).
