1: The Brotherhood of Sleep
Prince of Darkness gets far less respect than it deserves, in my humble opinion, but even its detractors own up to the spectacular creepiness of The Brotherhood of Sleep dream sequences. Years before the found footage craze, PoD showed just how scary shaky-cam video tape footage could be. Everything about the sequences is great – the garbled electronic plea for intervention, the daylight horror and of course the nightmare slowly, weirdly emerging from the church.
2: The Canister
PoD loses a lot of people when ultimate evil is shown to be in the form of an ancient canister of swirling green fluid. But I love it. First, the design of this prop is top-notch and it looks incredible on film, giving off this strange green light. Actually, the whole church basement set looks great. Second, the concept is too cool for school. PoD gives the Christian mythos a full-on cosmic horror treatment and as such, while Satan is powerful and evil, it is also an utterly alien being – so alien as to not have any real form.
3: The Carpenter Crew
While lead Jameson Parker does not do enough with his role, the cast is otherwise heavy with Carpenter alumni who do it right. Victor Wong (Big Trouble in Little China) and Donald Pleasence (Halloween(s), Escape from New York) memorably square off as Scientist vs. Priest. Dennis Dun (BTiLC) and Peter Jason (They Live, In the Mouth of Madness) provide some memorable comic relief. Dun has some of the best moments in the film as his character Walter understandably and utterly flips out when faced with supernatural horrors. Also, Lisa Blount (not a JC alum but notably in Dead and Buried) is just really easy on the eyes.
I love the fact that the heroes are a bunch of grad students. They are from all of these different disciplines (ancient languages, chemistry, physics, math), each discovering different alarming things about the canister and the history of the people that brought it into the church (The canister is possibly millions of years old, the texts are filled with advanced mathematical equations, etc.) You know they are all wondering if they can get a publication or two out of the ordeal.
They have no resources, being broke-ass grad students. They can't fight, being nerds. But they are smart and get a far better handle on the situation than an equivalent bunch of typical film undergrads ("college kids") ever could.
5: The Ultimate Horror
There is an apparently unstoppable, horrifying evil force that is attempting to bring something somehow infinitely worse into our world and humanity's only defense is a bunch of unprepared grad students and some teetering old guys. But it gets worse!
The Church once drew maps of the world that placed Jerusalem at the center of a round disc – the world. Then Science came along and showed that the world was a sphere with no geographical center. Then the Church placed the spherical Earth at the center of the solar system. Science then showed that Earth was just one of many planets revolving around the Sun. Then, before the Church could even get another iteration out putting the solar system at the center of something, Science revealed that our solar system is a tiny speck in a nondescript part of a massive galaxy in a universe of massive galaxies.
PoD takes it one step further – a step intended to horrify the religious person and scientist alike. Not only is our world a tiny speck in the middle of nowhere in particular – our entire universe is merely the bright positive mirror image of the "intended" universe of darkness and evil. Per the PoD mythos, the good Christian God does not even exist – the Creator of all things is actually the evil Anti-God of the Dark universe and we live in what is merely the unintended or perhaps unavoidable consequence of that dark creation!
That is some heavy stuff. Actually, our heroes could get like at least three publications out of it if they chopped it up right.