I really love how you interpreted both characters in this. Light in this one is like the 'bad boy' image most people would imagine. His face depicts that 'I don't care' image, and the open shirt reinforces it. Adding in the scythe really reinforces his thoughts and ideals in the manga; that he was 'God', that he was 'higher up' than everyone else, when in reality he was just as fragile as those around him. The lighting on his side really enforces that I believe. You see it as a punishment. For all his misdeeds, his messed up thinking, he has been condemned to hell as punishment, to prove just how wrong he was.
And then there is L. The way he is dressed and poised enforces who he was in the manga. He didn't care about his looks. He was a critical thinker, and was always trying to do what was considered right. The expression on his face says "I do not wish to stand out, only to blend in." Its like he's trying to keep people from noticing him. I've found people have commented about the apple, in both positive and negative ways, and here's my take on it. Ryuk loved apples, and at one point, L actually got his hands on a death note. I believe the apple is to signify his connection to both Light and the Shinigami, and I feel that subtle addition really brought out that meaning. Here the blue light would represent those things he'd tried to do in his life to bring justice, and because of it he was rewarded with the luxuries Heaven had to offer.
Now what I found no one seemed to comment on was the wings, or the destroyed Death Note. To me, those wings represent what those boys are to eachother. Without one, the other would be nothing. They are simply two sides to a coin, one the face, and the other the tail. Together they are one, a whole being. I believe the Death Note inbetween, torn and frayed the way it is, is to signify what it had done to them. It tore them apart, made them really turn on eachother, and in the end, destroy eachother.