Reddit mentions of ICO: Castle in the Mist

ICO is by far my favourite compared to SotC. If you're interested in reading, there was a book written (and English translated) that focuses a lot on the backstory of Yorda and the Queen. It's essentially a fan's interpretation of the events and well worth a read if you're striving for more.

I don't really read enough mystery/thriller to give recommendations, but here are some Japanese "normal" books I recommend (all Amazon links):

Night on the Galactic Railroad
ICO: Castle in the Mist
The Book of Heroes
I Am a Cat
Silence
The Samurai
Kokoro

Wallpaper the ICO graphic was pulled from. It's one of my favorites.

Edit: I'm trying to dig around for the source. Found some other resolutions from a scan it looks

Oh, I think it's art for the novelization but from the japanese publisher neonvision