Cagliostro appears in this movie as Spawn's mentor. In real life, he was an occultist in the 1700s who traveled Europe and Egypt and would eventually found Occult Freemasonry. He was also a noted charlatan who would eventually be imprisoned in the Bastille and banished from France, then tried in Rome for heresy, magic, conjury, and Freemasonry. He died in solitary confinement in the castle of San Leo in 1795.
In the Spawn comic book, Spawn is killed by a man named Chapel. Because the character was owned by artist Rob Liefeld the killer was changed to the character of Jessica Priest, keeping with the Church-themed name.
In one scene, Clown says "I'm not the Vindicator or the Victimizer or the Vaporizer or the Vibrator! I'm...The Violator!". In the Spawn comics there are five Phlebiac Brothers, which are denizens of Hell called Violator, Vandalizer, Vaporizer, Vindicator and Vacillator.
The Devil in this film calls himself Malebolgia. This is a name used by Dante in The Divine Comedy, however, it refers to a place rather than an individual. In Dante's work, the Malebolgia were the Infernal Pits, a particular place located in the seventh circle of Hell were the damned were buried, head down, in pits filled with insects.
The FN P90 and H&K MP7-PDW submachine guns used by Spawn and other characters in the movie are not genuine P90s or MP7s. Both weapon types in this film were actually heavily modified Ingram MAC-10s dressed up to look like real P90s and MP7s by the film's armorer, Harry Lu.
The intro song played during the opening credits is called "Satan" by Orbital. A remix is featured on the official soundtrack, but it may be hard to distinguish because of a lot of added electric guitars.
The heavy metal band Iced Earth, which has made an album based on the comic Spawn, were offered the opportunity to be on the soundtrack. They turned it down, because they thought there was too much techno music on it.