There's both a fast food kiosk at street level and a nicer upstairs patio with a proper view of the…read moretown and nearby mountains. Given the unusual lack of other restaurants, I happened to visit both before and after seeing the waterfalls.
The kiosk serves entirely average fast food. The chicken nuggets tasted like fast food chicken nuggets, but at least they were cheap. The upstairs patio is obviously a lot nicer, and has pretty good desserts. However the service is painfully slow, even by German standards.