Who is the narrator, can she or he read minds, and, more importantly, can we trust her or him?
Third Person Limited
You see everything in the novel from Connie's point of view. This is important, because if you saw it from someone else's point of view, you'd have a better idea of whether Connie's mind is working right.
As it is, all you know is what Connie sees; if she says she goes to the future, you've got to trust her (or not), because you don't have anyone else's perspective to help you out with that. By the same token, you don't get to see the world from Luciente's perspective—if you did, you'd know Luciente was real and had a perspective. As it is, she could just be a dream Connie's having.
The one time the point of view changes is in the last chapter, when you read Connie's medical records. They certainly give you a different take on what's happened in the book. Is it more believable than Connie's? Or does it just show that the medical personnel are even more confused than you are (or than Connie is)… not to mention a whole lot more evil.