Filmmaker Gregory Widen learned a little, I think, from his previous outing with Highlander: it's not enough to get Sean Connery and have ridiculous immortals and beheadings. You need some fresh ideas that can live past their shelf life of the 1980s without going into complete repetitive mode. With the Prophecy he has a sturdy script chronicling the lapse of faith with an ex-priest played by Elias Koetas and how he comes into the investigation of a series of crimes involving burnt up dead people and lots of signs pointing to a prophecy of thins involving the word "dark".
On the side of themes, things are fine. But he knew that his script needed some uplift and, as with Highlander, needed a star to carry it over past the genre fans. Christopher Walken was his key, and it's one of his true-blue "Walken-iest" performances. He's playing a supernatural creature of the underworld in the guise of himself, so he knows it's time to go to town, and he does. I can imagine Widen smiling to himself as he wrote such lines as "Study your Math, kids", wherein Walken could sink his teeth in and make it an awesome nutbar of a performance. He still brings the creepiness when he needs (in this case all he needs to do as Gabriel is to stare), but it's the superfluous sense of humor, a timing that might be deadpan if it weren't for the evil angle, and it works wonderfully.
The rest of the film is good, I should still say. This is one of those underrated 90s movies that has people who like it or don't, which is the way it goes sometimes (at the least, I would imagine, the first film has a better rep than the sequels, filling up a trilogy which is slightly inexplicable given the ending of this film). Actors like Virginia Madsen, Eric Stoltz, Adam Goldberg and Amanda Plummer take up very good space for what they need to do, but it's Viggo Mortensen who comes out on top as the most inspired casting after Walken. His scenes as Lucifer are tense but calm, if that makes sense, and he has that quality that one may have seen in De Niro in Angel Heart. He's so convincing as him that he makes his own a character that's been repeated countless times - and not just because of the "Mother's feces" line. He notches up the rank of a solid genre piece like the Prophecy into something of a kind of minor must-see - at least for those of us that will dig Mortensen in almost anything.