Let's get to the point from the off: Deeper is better than Tunnels. I guess the next question is: how is it better?
First up there is the pacing. Deeper begins where Tunnels left off, with unlikely protagonist Will Burrows still on the trail of his lost, curator father, and finding his friend Chester on board the train that is transferring him to the subterranean hell-hole that is The Deeps. The authors have pulled out the stops in grabbing - and maintaining - the reader's interest; something sorely lacking in the first book.
Secondly there is more depth given to some of the main characters, the relationship between Will and Chester moves from the one dimensional, making the reader care a little more for these two guys. Will's estranged birth-mother is also given some airtime; her personality - feral - based upon her fugitive lifestyle as she keeps one step ahead of the relentless Styx.
To discuss plotline so soon after release would not be fair on those who have not had opportunity to read the tome. Lest to say that I found it an entertaining, albeit mirthless, affair.
So why three stars? Well, for this reader, some issues remain. The narrative remains clunky in places and it is becoming increasingly clear that one of the authors is adept and the other, quite possibly, isn't. The book also comes in at 675 pages and is still in need of a good edit. It has the `well proof-read, but poor copy edited' feel of a self-published book, and the publisher - not the authors - must take responsibility for this.
Gordon's and William's subterranean opus continues. No-one doubts that the world they are creating is inventive and, in this post-Potter hiatus, refreshingly different. I will stay with these guys in the hope that there is light at the end of the tunnel - heck, I'm intrigued enough.