Why has the movie "The Green Lantern received such terrible reviews?

They said is was over produced and the story wasn't didn't follow it's original Comic Book lore. Ryan Reynold's pulled the character off brilliantly, and the love story and it's tension between him and Blake Lively was very believable. Superman, Batman ALL followed different directions as the several variations of the movies unfolded to EVERY ONE'S delight, what have I missed here?