The movie didn't start very appealing for me (skipping to a scene later in the movie to keep some tension or to tell us where it is about to go). The character introductions seemed OK, but not really something I thought I'd be get too excited about. But once it gets going (after 15 minutes I reckon), it really never lets up. Yes you can call this a road movie if you want to.
Axel Stein is known in Germany for his comedy skills rather than his acting skills. That might change with this movie. It's an action comedy, so he still kind of stays in known territory, but the way he plays it is exceptional. Even more amazing that he wasn't the first choice on this (which is discussed on the audio commentary of the movie). Another surprising thing (at least for me): Jasmin Gerat was really good in this movie. Even in a movie I really liked ("Mann tut was man kann") I thought she was the weak link, but in this she really cherishes.
While I still haven't seen "Bang Boom Bang" (but a movie he did in between), I like the way the director takes this. For some it might feel too long or they might be annoyed by the characters, but if you let yourself get into the journey with them, you will have a lot of fun (and some suspense)