I believe the Heaven is explained. At least it's shown what it is and is kinda understandable. The whole book is written from the point of view of the main cha

I believe the Heaven is explained. At least it's shown what it is and is kinda understandable. The whole book is written from the point of view of the main character in a form similar to a diary. Diegetically it makes sense to not explain everything because the character knows it all already. I kinda like the idea of it but in practice it left me confused most of the time. I fully admit that it might be just me. I like new ideas and non-linear story telling (e.g. I absolutely love Use of Weapons by Banks). I like when my books make me go "Fuck yeah!" (excited) or "Oh fuck!" (surprised). This one made me go "WTF?" (confused) more than I like.