This was almost as good as the first. My only complaint is the repetition of facts we already know. Probably 3 times, we are reminded about thermoclines, several times we are told the same facts about the Mariana Tench, and then constantly about the accident that happened in Meg Origins. Constantly. We get it. We know all this.
There's also the exposition thing. It found some sort of lazy ways to explain things, and it goes way over the top. We even have a villain monologue that explained his entire plot.
But besides this, I really enjoyed the fast paced plot. Poor Jonas is going to be in therapy for the rest of his life.