During the scene in the bar with Mystique and the prison guard the person on the TV is called Dr. Hank McCoy, this is the real name of X-Man The Beast.

The young girl who runs through walls and soldiers when the mansion is attacked is Kitty Pride, aka Shadowcat from the comics. She is also referenced in the first movie, as "a girl in Illinois who can walk through walls."

Magneto is reading 'The Once and Future King' by T H White. In the novel Merlin is trapped in a crystal cave - Magneto in a similar plastic/glass cave.

When Kelly Hu first read script for the role of Lady Deathstrike, she was told that her character's name was Anne Reynolds. Brian Singer used this technique for every role, to prevent information leaking out on which characters were to be in this film.

This is revealed on the bonus disc of the DVD. Ronnie Drake (Iceman's brother) is the one who alerts the police of the fact that there are mutants in his house when Wolverine, Rogue and Pyro are there with Bobby. On the DVD, there is a section called 'Galleries' which has a shot of Ronnie's bedroom. On his wall, there is a big poster with 'Mutants Suck.' written on it, and another which says 'Is he one of them?'

One of the files on Stryker's computer is labeled "Project Wideawake," which is the codename of the project to build the Sentinels, giant mutant-hunting robots that the X-Men have fought on numerous occasions.

In the bar scene where Hank McCoy is shown on the TV he is in some kind of debate and are speaking to a person who he calls Mr Shaw. In the comics Sebastian Shaw is the real name of Black King, the leader of the Hellfire club and a deadly enemy of the X-men.

After Mystique beats on all of the guards (entering disguised as Logan) with some flying maneuvers, she goes sliding into a room giving the finger. Not only was her hand edited to be palm and fingers down in the movie theatre previews, but this is the second time a mutant has given the finger the X-Men movies. The first time was Logan to Cyclops with his claw in the Statue Of Liberty.

Many of the attack moves that Wolverine does during the film, especially during the mansion invasion, are the exact same special finishing maneuvers used in the video game 'X2: Wolverine's Revenge' which was released shortly after the film.

The entire computer list that Mystique is looking at on Stryker's computer are mutants from the Marvel universe: Guthrie (2) are brother and sister Sam and Paige, Cannonball and Husk, Keniucho Harada is The Silver Samurai; Garrison Kane is Kane from the Weapon X program; Remy LeBeau is Gambit; Eric Lansherr is Magneto, though it is supposed to be spelt Erik Lehnsherr; Artie Maddicks is Big Eyes; Jamie Madrox is Multiple Man; Xi'an Coy Mahn is Karma; Maximoff (2) are the brother and sister Pietro and Wanda, Quicksilver and Scarlet Witch of the Avengers, both are the children of Magneto; Kevin McTaggart is Proteus, Son of Moira McTaggart; Danielle Moonstar is Mirage, Psyche; Ororo Munroe is obviously Storm; Franklin Richards (You only see the "Lin Richards" ), the son of Reed Richards (Mr Fantastic) and the Invisible Woman (Sue Richards).

In the scene where Mystique is printing the files on the security guard and she spots the Cerebro folder, there are 2 more folders there as well, Omega Red (one of Wolverine's enemies) and Muir Island (Banshee's home in Scotland).

When you first see Magneto, he is reading a book named "The Once and Future King." Near the ending, Professor Xavier is teaching his class while the sound is fading out but he says, "Have any of you read a novel by T.H. White named 'The Once and Future King?...'"

When Stryker enters the code to enter Cerebro 2, listen carefully - it's the 5 note sequence from "Close Encounter of the Third Kind".

One of the security guards listed in Stryker's files was Tom DeSanto, the executive producer.

The little mutant boy, Artie, (the one with the green forked tongue) is indeed an actual character. Anyone who has read the comics knows of the "infamous" Artie and Leech.

In his plastic cell, Magneto is reading "The Once and Future King," a book about King Arthur. Arthur's supposed final resting place is called Avalon. Avalon is also the name of one of Magneto's earth-orbiting bases in the comics.

When we see Magneto for the first time in his plastic prison, the music that is playing in the background is the same classical piece that plays in Hannibal Lecter's cell in Silence of the Lambs.

In the first scene where we see Stryker, where he is fingering the stab mark on the President's desk, he appears to have on a ring with the Hellfire Club's (from the comics) trident symbol.

In the first movie Rebecca Romjin-Stamos had to wear yellow contacts. In X2, they were added digitally, that's why they look a different shade of yellow.

The foreshadowing of Jean Grey becoming Phoenix occurs throughout the movie. Whenever Jean Grey focuses on her abilities you see a flame in her eyes. eg. during the attack on the jet, in the dam spill way, and during the sacrifice.