Great idea, great comp. Needs technical work. First, that hand on the shoulder is very awkward. I understand its hard to do in PS.. it takes a lot of practice. Add a shadow and soften the outline of the hand, fix the color, make it smaller and fix that "web" between the thumb and the forefinger.
Aside from that, the pic is overall cool tinted and that needs to be fixed. Could be brighter also.
Oh and the cutting off of the feet should of course be mentioned.
I agree with kellylindsey...it looks like you cut out the person on the right - I'm guessing with the selection tools?
I think you can accomplish this with a more natural look the way that I did this - basically by using the eraser tool and layers. With very careful erasing I think you could accomplish this, so for example, with the person in the middle, he would be on a lower layer and the guy on the right would be on the top layer. Then you just start erasing where the guy in the middle is so he starts coming through. Here's a link to the one I did, although mine wasn't as complicated as yours since I didn't have as much interaction with myself, lol
It's pretty goofy but I was just messing around and it was my first attempt at this:
Have someone else have their hand over your shoulder like that, and then just edit yourself in their place. Getting small objects to not look pixelated is super hard. Try messing with the "Refine edge" dialog when you have a selection tool equipped.