I was really enjoying the game until the High charity mission... from then it kinda went downhill in my opinion. Not only do I personally hate flood missions, but the story just kinda lost its oomph after high charity. It all kinda tapered down, and the last mission was really not that great at all. The final movies, both of them, were awesome though. What a great ending. Although it couldn't have killed them to show a shot of all the flood getting vapourized or something. It seemed kinda rushed.
Still didn't spoil it overall though.