Face might seem a touch "plasticy", would like to see it a bit more natural ... but that falls into preference or style. What are you using for your conversion to BW?
Nice expression, good connection with subject. Congratulations on BW exploration - to me a good BW is much more difficult to achieve than color, but then I have a definite bias for BW
Composition - perhaps more room to right? Lighting of sand is eerily similar to that on the subject - my mind wants some separation in those tones - unnatural and not what I expect to see (but maybe that is just me).
I agree with RustyBug re complexion. See circled areas on forehead, cheek, etc. Perhaps a stylistic choice - to me, overworked. Eyes and mouth are soft.
Plane focus appears to pass through sweater and arms, not his face. DOF could be that shallow if lens was wide open.
<edit> Looking again, his forearms and hands appear to be well in focus - how many and which focus points were you using? Dynamic with closest object might produce this result.
Movement of head? Shutter speed?
Exif isn't available - conversion method?
And my sincere apologies - Welcome to Photo Critique. I think you will find this a congenial group with an interest in sharing and helping each of us grow in our craft. We are all here to learn.
Tweaked a bit on tones and sharpening to try and balance the draw toward his face.
His pose and facial expression kinda remind me of a "little monkey" ... projecting a playful spirit ... a fine capture, coaxing and capturing the emotive (which is why I am not a portrait photographer). I'm better at coaxing rocks than people.
I quite like this one. joyous expression and good separation between subject and background. The boy's face may perhaps be a be a bit close to the bright background in tone. More separation in tone may concentrate more emphasis on his face and expression. Consider selectively darkening the foreground and background for better subject separation and perhaps a bit of a crop to tighten the composition.
