Originally Posted by DigificWriter
First Class HAS no major continuity issues insofar as the first trilogy is concerned; the only two things it messes with are Xavier's line in X1 about Magneto having helped him build Cerebro (which really isn't an issue) and the scene at the start of The Last Stand where Erik and a still-bipedal Charles go visit Jean (which could be explained in any number of ways).
Yeah, I don't really see what the continuity issues are. Charles said Erik helped him build Cerebro? Big whoop. Charles walking in X3 flashback? Again, big whoop.
I've only seen FC twice, so maybe I'm missing something.