I see about the zooming. PixelJoint has the interpolation set to Nearest Neighbour (there should be no blurring), but some browsers don't support it, most notably Chrome. In other browsers, the zoom feature doesn't cause any blurring.
I see what you mean. Though about the zoomed in sprite: I know there is a Zoom in feature, but the zoom always blurs the pixel art and I am not too fond of that.
You don't need to have the zoomed in form, PixelJoint has its own zoom feature.
I think you have a few too many lone pixels here, they make the piece feel a bit noisy and unpolished. I don't think you need the lone black pixels on the socks or the black internal outlines on the shoe stripes and gloves. You have several dark greys in this that could do the job just as well without looking as noisy.
I am using Chrome so that would explain why I see the blur. Thanks for that piece of information.