I didn't like it as much as others do.
It is a typical German movie: Most actors are not bearable, the writing is bad and of course there is a plot twist.
A movie about hackers cannot be accurate about hacking, otherwise it would be boring as hell, but just throwing around buzzwords like "0day-exploit" and "he can read machine code" makes it even worse. What exactly is the IP tracer inside the hammer?
And of course there is a plot twist–Fight Club much?–but with a twist inside the twist. I didn't see that one coming, so that's good for the movie.
But on the other side, just creating tension by not telling the audience what's happening is also bad.

The IRC meetings are well done in the subway where you can be anyone and no one knows who you really are.

Hacking the BND makes it really funny, I liked that part, and the Blinkenlights of the pharma company. These were things that could have been true. However, unbelievable was hacking the TV station and printing the finger in the stock prices, they hacked the sender, so the users at home at the TV should have seen the finger but not the newscaster. She does not see the same screen.
Hacking the NBD (Why was it not allowed to call it NPD? So bad...) was a very good deed, but why do the Nazis afterwards know exactly who hacked them and from where (the van). And why do they all have baseball bats for a presentation of their party?

About the actors: They are native German speakers but all they say sounds like a bad synchronization like from American movies.

All in all a decent typical German movie: Bad actors, storyline copied from many successful other movies and the actual main part (the hacking) is too short.