Starting writing my third book

While I await the arrival of the draft copy of my second book to go through final proofing, I have already begun writing a new book set in space, during wartime. I am backing off the narrative for this one to inject more 'game' into the experience, where the reader will need to determine the names of the crew and what skills they have.
It will be written to be replayable, with a different experience each time (unless you get really lucky and get all the same events happening). I'm hoping this kind of book is one that gamers might take with them when travelling, to give them something to do when breaking out their RPG books might not be appropriate.
If it works out, I may write a horror book based on the same system.