Although this story stars primary school children, it deals with some mature themes, and the two main characters themselves are quite mature. Don't let the age of the characters turn you away.
Kami-sama ga Uso o Tsuku was really short, and I was sad to see it end so quickly, but at the same time, I think it was the perfect length. It was a beautiful story, really touching, well-written, well-illustrated, with lovable (and also despicable) characters. What I particularly loved was how introspective it was, and how tightly-focused it was on the main characters; it's my kind of read. Maybe I wanted more of an epilogue, but I think that's just because I'm spoilt; the ending is very good, just as it is.
Naturally, because they're simply children and this story takes place in their childhood, I wonder if there would have been a future for them... but nevertheless, because of their simple commitment and their mature understanding (and because I just want to), I choose to believe there will be.
Highly recommended for anyone looking for a short, complete, drama-romance slice-of-life. I'm looking forward to this Ozaki Kaori's next work... One day I may even try her older work, despite it being shoujo.