The street corner where Neo and Smith fight in the crater is the same corner from which Neo made his phone call at the end of The Matrix (1999) - the corner of Pitt, Hunter, and O'Connell Streets in Sydney, Australia. You can see the phone booth to the right when they hit the ground.
Many of the "raindrops" in the final fight between Neo and Smith are actually single lines of Matrix code, similar to those on displays seen in the "real world" throughout the trilogy. This subtle effect was added to imply the Matrix was beginning to destabilize. This visual trick was easily seen on IMAX and larger movie theaters, but can be seen on smaller televisions as banded rain that seems to "jump" like static during close-ups of the fight scenes.
In an unprecendented simultaneous global release, this film opened at exactly the same moment in every major city in the world on November 5: 6 a.m. in Los Angeles, 9 a.m. in New York City, 2 p.m. in London, 5 p.m. in Moscow, 11 p.m. in Tokyo, November 6 at 1 a.m. in Sydney, and at corresponding times in over fifty additional countries worldwide.
Only one full-size APU was ever built. It was completely rendered in Auto-CAD, and parts were made detachable, so that for scenes involving different pilots and APUs, the detail work could be altered. The full model weighed around two tons.
During the scene at the club, The Merovingian is wearing his tie in a fashion that is actually called Merovingian tie-knot.