The ending was...
... a complete failure.
It was building up and up till the end. And when it arrived all we got was a cheap shot attempt at an ending. Really, I say we deserved a whole lot better than that. Either have both characters survive or have them both die in the canyon. Having them both die in the canyon just before the rescue arrived would have been a better ending. It would have made you feel sorry for them, since they were so close to being rescued. All the finale made me feel was cheated in some way.
2732 zombies were harmed in the making of this movie - L4D2: Dark Carnival finale.