Like the first X-riff, I didn't think this one was as good as the likes of The Matrix 1&2, Bourne Identity, terminator 3, etc. Not enough esoteric hilarity, etc. However, some of the best riffs weren't gags on the film as much as on the riffers. Kevin's e-mail to Bill was funny. My favorite of those though was when Magneto said "You should have killed me when you had the chance!" and Bill says "Ahh, sounds like your average Christmas at the Corbett house"
The hardest laugh I had though was the "I like turtles" line. In a previous riff, they tried to reference the turtle kid, but it fell flat because it didn't have anything to do with the movie. When that soldier pulled off the mask and had the same darkened eyes and everything, my brother doubled over with laughter and I couldn't stop laughing until I had to wipe tears from my eyes. Good job guys.
They did miss a golden opportunity with their cerebro bit, when the kids escaped and they riffed "Everybody down to the wine cellar" they should have followed it up with a reference to Edgar Allen Poe's "The Cask of Amontillado"
Fortunato!
Cerebro!
Amontillado!
And they probably should have had one "Zippo" riff for pyro.