Hey Neko! This is a great sketch Their expressions are really sweet, it makes me happy just looking at them
I don't see anything wrong with this picture, my first impression is that it was drawn quickly, though. Some of the lines look a little shaky and not all of them connect. I know with manga, there are times when you don't connect lines and leave a blank space, but with areas like Naruto's hair I think those strands should connect at the ends to form the spiky block shape of his hair. Adding a little color or shading could finish off this drawing nicely, too. If this was just a sketch, and if you're drawing digitally, you can do quick coloring by just making a new layer and setting it to color or overlay and splashing on bits of color. Or you could even use the bucket tool x)
Another thing you can experiment with is brush size. I see that you did the whole sketch using one size. If you would make certain lines thicker, and others thinner, it might help too.
Awesome job! This is a really sweet picture Keep drawing, and let me know if you'd like any more reviews!
The bad news is we don't have any control. The good news is we can't make any mistakes. -Chuck Palahniuk
Dogs love their friends and bite their enemies, quite unlike people, who are incapable of pure love and always have to mix love and hate. — Sigmund Freud
Their expressions are really sweet, it makes me happy just looking at them 
