I'm going to be very honest. I don't really like the sprites you came up with. I'm not so sure a mix of GB and ALttP is a great idea. And, if you're going to do black outlines, I think the characters should be more "puffy" otherwise the black lines overcome the actual details of the sprite and it ends up looking like a mess. If you want to make the proportions look more natural (as opposed to puffy), you're probably going to want to go bigger with the sprite res. I could be totally wrong though, it's just what my eyes are seeing. I don't know a lot about spriting properly.
However, if you just want to fix up the sprites you already have, here is my more than slightly less than professional advice:
I think you could try to make the head not so flat on top. Also, when walking up/down, the foot and leg movement need to be more discernible; it's difficult to see what's moving which way because the detail doesn't allow for proper focus on the right aspects of the animation, as far as the leg movement goes. Leg movement sideways looks good enough though.
Furthermore, for sideways movement, when his arm is extended all the way back or forward, I think you should see the hand pop out a little bit from behind him on the other side. At the moment, it almost seems like he only has one arm when viewed from the side. Finally, I think the feet look a little rough with the outlining. I've been there before and it can be tough to keep proportions and to keep them from looking awkward. They are okay, but you might want to try to touch them up a bit if at all possible. I think it might just be that the bottom of Link's feet need to be flat instead of rounded, so you might want to try making them flat on the bottom.
My brutally honest opinion, however, is that you should start over. I'm not trying to be mean. If I wanted to be mean, I would just tell you that they were great sprites. I'm just trying to help you become a better spriter. For some people, it's easy to sprite, for others it takes a lot of hard work and practice with trial and error. As for me, I used to utterly suck at spriting, but I've practiced quite a lot and now I'd like to say that I can get by fairly well (though I'm still not very good, unfortunately). Just keep at it, listen to the advice of people like SinkinDevil, and you'll have some good lookin sprites to be proud of.