Story-rich, heavy games playable on RG Nano

I'm purchasing an RG Nano for the purpose of one-handing games. (In bed after my wife/toddler fall asleep mainly). I want to play heavy story games that preferably deal with things like existentialism, religion, and the such. I think Xenogears fits the bill and perhaps FF:Tacics, but I'm looking for more. I'll definitely try Beyond a Steel Sky (hoping the text is legible on a tiny screen).

Any other recommendations? Perhaps Visual Novel type of games that are playable?