Wow u posted so much of them, like this its hard to concentrate on each one of them and give them the time they deserve. In global what can I say it how they look quite good. Some of them are a lot out of proportions. Some of them look quite nicely. But next time u start drawing find some body refrence and dont worry mostly artist do that. Shading is still preety simple on some pictures it fits but on some maybe u should add more shadows or so.
But there are 2 pictures that I really like A LOT. The one with Cloud - great choice of colors really and it fits the BG sooo much, its great. and the next one is the one with naruto making heart for sakura

some poses are out of the proportion but it is replaced with the cherfullness of Naurtos clothiung and the global idea so to me it just doesnt matter that much