REVIEW WITH NO SPOILERS
Do not think that I disliked this anime because I scored 4. I did it because technically the anime is lower than the average.
You will only enjoy this if you're a football fan, like I am. Then you will probably find fun here... like I did.
But I can't ignore the bad animation (this is an anim produced in 2010 man!) and the ugly and strange design of the characters (whats up with their noses?).
And there is nothing fun in the story besides the football (you have no good comedy or any healthy fan servisse here).
So if you are looking for an anime about professional football, and just that, Giant Killing will satisfy you.