I don't know how to explain this. I just don't like it that much. It just feels a bit flat and bland compared to some of your other stuff.
In terms of lighting, I'd probably try to give him a bit more perspective, ie, darken up the parts a little that aren't seeing as much sun, like his left arm and parts of his legs, then try to blend the shadow on his torso more naturally instead of having such a hard edge between it and the lightened parts. And also, the way you've shadowed it, it kinda looks like his legs are around the wrong way. The position he's pulling with the way you've got him looks a little strange, like he's kicked off a vertical wall to his right on the way down. That's just me though, you may like it the way you've done it, but it's something I noticed. Apart from that, I like how you've given the whole image a kind of pen and ink type filter to it, but it possibly needs a little more to make it slightly more dynamic. Perhaps some kind of text, ghosting/blurring, or something I can't put my finger on just yet. There's nothing really framing it either, which could help to draw the eye more towards an intended focal. I dunno, I'm ranting I think.