I like that you highlighted him with the flash to make him stand out. But the rest of the photo is kind of bland. I dont know if you could bring out any more color in the sky, or perhaps shoot him from a different angle to make him larger (and see his face), or from an angle that accentuates the danger and adds interest. This type of shot is hard but I think your off to a great start!
awesome photo, genuinely looks kinda risky (and fun ) - just for a tip coming from someone who has never really taken photos of rockclimbing/bouldering haha - photos that make me think woah that looks dangerous - are the ones where its closer up and the background (opposed to his immediate background i.e. the ground in this case) are not in full focus or are cropped out through the composition of the photo. What I am saying basically is i like the photos that are close up and give the illusion that the climber is a lot higher off the ground than they actually are.
just my opinion, i don't think i put it in words too great but hope it helps some how . Still an awesome shot you got there like I said .