A review by bluemiriam
Mirrorland, by Carole Johnstone
This is one of the few books that I think actually used twins well. We heard everything about their past from Cat's perspective, but the diary entries and little flashbacks throughout the book made it pretty clear that El wasn't just an evil twin but a person with a totally different way of coping. Everything about El and Cat's young life was so unhinged in a really interesting and compelling way, and I enjoyed watching Cat figure out the connections between her childhood games and the real trauma that she experienced.
I was very invested because of the writing style and Cat mixing her half-memories in with the current day events to create a really great horror atmosphere.