When the 20th Century Fox logo fades away, the X in the logo stays for a second longer before it also fades away.
This is the only X-Men movie that does not use the "flipping comic pages" Marvel logo, as it did not exist at the time.
The X-Films' title sequences features a weapon used by the villain of each film, backed by the X-Men's Cerebro device.
In this film it is a sequence of genes and chromosomes, reflecting Magneto's mutant revolution and his mutation machine.