AndreasR how about rewarded ads using Admob?
For reward ads in AdMob you have to add a third-party network to AdMob, for example Chartboost. But this game uses chartboost directly, so this is the better way (in my opinion).
Moreover the CocoonAds plugin for c2 do not support admobs rewarded ads yet.
I consider an update once the c2 plugins have been updated
I'll keep you posted