SFX have published an interview with writer of The God Complex Toby Whithouse in the interview Toby mentions the following.
The Doctor, Amy and Rory find themselves trapped in a 1980′s kitsch hotel. The geography of the layout keeps shifting and changing, so they’re trapped in there and they’ve lost the TARDIS. There are other people trapped in there, two humans and an alien. And also with them, are nightmares. Each room contains a different nightmare. And some of these nightmares are specifically the personal nightmares of the Doctor, Amy and Rory and the other people in there, and others are clearly nightmares that belong to other people who have been in the maze before and have died there.