Bullet review:

+Definitely the most anxiety-inducing book of them all, you never once feel like you get a moment's rest alongside Mathijs because he might be arrested and tortured at any point in the book.
+Interesting character development for Mathijs (and to a lesser extent Kirchhoffs).
+Some very brutal scenes, but written in an engaging way still.
+Lots of action in this one.
-Ending is a bit ambiguous. It didn't bother me TOO much but I can see this putting people off, since this is the final book in the series.