oookay...
Alright. all round you did an OKAY job. The shading for the 2 flat rocks are off, if the top parts are facing the light, they should not have any sort of shading on them the same goes for the one beside the guy with the guitar, plus with that rock it looks like you missed a part of it, it doesn't look complete. The shading on the island thing hold up that castle doesn't go along with the jagged rocks, making that part look like shit sorry to say. The same for the rock in the upper right corner. and the perpective for the rock right beside the castle ( to the right) is off.
Also, even though you gave Mcj more then usual muscle, the pose just made him look girly and the anatomy is wrong as well. The guy with the guitar, if you were to move his guitar out of the way, his legs would be to small, you need to extend them.
I would suggest deleting this current pic and going over, find all the mistakes then re upload it. because this... this just looks like crap.
I know you could of done better then this. :/