I honestly don't think that that's a problem. Like I've said, the screenshot I've postet isn't really pixel art, it's just a postprocessing and rendering test for pixel art with some lit spheres.

This is what it looks like with an actual pixel art image (which I obviously didn't create):



regarding the pixel size: The downscale version in the forum here has too small pixels, yes
but at the actual size it has 4x4 pixels and I think this is enough :S ...