Some photos here visibly lack in sharpness (focus on the eyes missed in 2, camera shake in 3), but other than that you mostly show children in playful situations, which I appreciate. But then I am no portrait photographer at all, so maybe I am the wrong person to give you a first comment on your photos here... ?!?
In the first I like the fact that you had that boy (?) climb the tree for the photo, but his smile looks kind of forced.
The second, as was mentioned, is not focused well enough. I also deplore the fact that his hands are cut off ... he might be sitting on a seesaw and holding on to it, but we can't see it. On the other hand, there is quite much room above his head, more than is actually needed.
Well, nice idea but camera shake --- Photoshop canNOT really remedy that when it happens.
The fourth is nice, his expression is VERY alert, his eyes become so big and round and dark, lovely, but where are the tips of his ellbows???

I'm not sure (with the size of the picture and the conversion into black and white) whether this one is TACK sharp on his eyes, but what I like, next to him looking so attentively, are the dimples in the corners of his mouth. Nice quarter-smile here

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This one would have been my favourite of the whole bunch (I just love green backgrounds and find they work well with faces! Mostly so when they are as blurred as the background is here), if it weren't for the centred composition. He looks to the right and therefore needs space within the frame to look into (I think), so it'd have been better if his face had been more on the left. All the space behind his face is not really needed here.
Nice idea, even though it has meanwhile been done often, but I am not sure this photo is entirely sharp. I don't think it is. I take it, these two are yours?