Constructive criticism is about content, not tone. Someone may be out of line for being a jerk but that doesn't invalidate their points. You know, like Wittgenstein.
Bad criticism is, "This is stupid and ugly and boring."
Criticism that is constructive but delivered badly is, "This sucks so bad and here's a detailed theory why."
Usually that kind is actually more helpful (I find in my own writing) because the person is logical and yet also passionate. Yeah, they can be wrong about a lot of stuff but they also give you a fresh perspective on the piece outside of all the fans and developers who are already really really close to the game.
And I already said that the real negative stuff wouldn't be posted here. In ten minutes I was able to find a slew of threads on other boards and blog reviews that strongly disagree with some major points on the writing and general execution of the story telling in the game.
Again, I'm not saying invite people to be nasty and harsh. Just be the bigger man and transmute that evil into good.