A huge rant on how crappy the ending of a game is does not make a sensible introduction to an 8.5 rated game. No way would I buy a game after reading that no matter what the rating at the end.
I've not played the game. However, if it is anywhere near as good as you say it is during your review, then you've done the game and company a great disservice. I respect that you don't pull your punches on what is wrong with a game, but the intro is not the place for it. It puts your readers in the position of reading the rest of the review through poo-tinted shades.