I agree with the eye comments, but to me shot 3 looks faked. Is that kid really on the sand or is it a background merge? I'd expect the feet to be sunken in, sandier legs, and he maybe looks a little out of proportion...
I do quite like the 4th shot though! Not sure if that's another background merge or not, but if I hadn't seen the image above I wouldn't even think about it so that's pretty irrelevant.