It starts out pretty boring. It has the expected wonkiness of a dreamscape, but with the added focus of a video game-inspired plot: our dreamer travels through the twelve doors to visit various worlds and subworlds, collecting the "effects" along the way. But it's not quite as simple as that; there's also something off about the times when she's supposedly awake. She pinches het cheek to wake up, but even from the beginning it's implied that she's just entering another layer of the dream. As the manga builds up to its climax, it starts becoming a bit more interesting, if only because it starts becoming more confusing and complicated in its portrayals of layers of dreaming and peoples' identities.
The main character always has her eyes closed, probably to indicate that she's asleep. I don't particularly like that technique though; I feel it makes it harder to connect to her as a character because it's harder to read her expressions. There are quite a few eyes and faces in the backgrounds, several of which reminded me of Aztec carvings or something.