I suggest you skip this "second of a trilogy" movie an wait to the next one I did not read the book, but I did see the first film and thought it interestingly different. This one, however, is not. In fact if you miss the first 5 minutes would not think this was a sequel at all but just some generic future apocalypse horror.
Having escaped the maze in the first film the runners spend more than 2 hours getting precisely nowhere. There is no story, only running about in a CGI world taken straight out of Bethesda's fallout games. However at least in a computer game you can interact with the world; in this film you are stuck in an anxiety dream you can't escape from, forever pursued and unable to get away from the bad people who want to kill you. The plot twists are lame, for instance the group at one point get separated because a person, who was specifically asked to prepare for departure has to go back for a trinket she apparently forgot to collect earlier. I wrote better plots (and was chastised for them by my English teacher) when I was 11.
The characters one dimensional, spending most of their time "caught in the headlamps" staring at stuff when they should be running. The dialog is painful; I'm used to those ubiquitous words "Hang On" being used in almost every film, but this film is just full of such stuff.
Having said all of the above, the cinematography is pretty good and full marks for the type casting of "Baelish" (Aidan Gillen), an actor I never tire of.