Sigh.
What started out as one of my favorite shows of the season managed to descend, as many anime seem to do, into unintelligible crap towards the end.
Others have said this, but how could Kanade have gotten Otonashi's heart and be in the world long before he gets there? Does the timeline in our reality not impact theirs? If so, why aren't there Japanese schoolchildren from ancient Japan who died tragic deaths?