I think he means something like motion blur (not really, but..). You know how when you take a snapshot from an anime and the image isn't very refined, with weak edges and all?
That's what I see anyway. It's more evident around the comet. You can have polished up motion-blur, and then there's the unclean sort of blur. I think it falls in the latter one a bit.
Even the stars upon closer inspection look unfocused compared to the foreground and text.
I'm not making much sense, am I?
PS, I'm being picky.