My German is almost nonexistent so I'm a little confused about what a knusperflake might be. In fact, I'm not really sure how to pronounce "knusperflake” either, is the "k" silent? I can only assume that it's some kind of cereal, either a rice crisps, or some kind of corn flake. I assume this because these are two common cereal type substances often used in chocolate bars, and Ritter Sport isn't really known for putting strange things into their bars. Ritter Sport tends to make classic combinations, but they use high quality ingredients and make them very well.
After eating this bar I'm still not 100% sure exactly what kind of cereal it is, but I'm guessing it's probably a corn flake. It seemed a little too dense to be a rice crisp, although it did pop in my mouth a little. Whatever cereal was chosen, it worked very well with the bar. The cereal was solid enough that it wasn't lost in the chocolate, but it also didn't dominate the texture either. The key was not only the type of cereal being used, but also the fact that this bar had a really nice ratio of chocolate to cereal. The cereal was very well distributed, so I got a little crunch in each bite.
With the high quality you'd expect from Ritter Sport, and a nice little crunchy cereal, this bar was OK. If you happen to know what a Knusperflake is, please let me know.