The criterion given is this:

"More than 10 accepted answers with score 0 and 25% of total."

Now I was going through my accepted answers and I saw that $$14$$ of my total $$40$$ accepted answers had score $$0$$, which is $$35\%$$ of total. Now I went ahead and checked who the system had awarded the last badge to. And that guy had $$12$$ of his total $$48$$ accepted answers with score $$0$$ which is $$25\%$$ of total. Now I think I am a "more" Unsung Hero than that guy. Even more so, if my next $$20$$ accepted answers are all of score $$0$$ which would make make my tally look like $$34$$ out of $$60$$ accepted answers with score $$0$$, which is $$>50\%$$ total. I think that is "more" Unsung, but the badge system disagrees with me.