Obviously, some things don't make sense. The first being Sabertooth. They're written completely different here and in X1. It's almost as if they're two different characters. Not to mention that he never acknowledges that he's Wolverine's brother. Then, there's the whole Professor X showing up at the end thing. So...if he was there and (it seems) aware enough to guide these kids out of the building why couldn't he tell Wolverine about it in X1? It's kinda weird that he wasn't aware of Wolverine being there. Especially since I'm sure the kids must have mentioned it.