These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Awesome Music: The third installment is certainly not the best film ever, but it features some good music. The End by Lori Denae is notable.
Complete Monster: The Warlock is an Evil Sorcerer who serves Satan, doing whatever heinous acts are necessary to gain more power. His plan is to recreate the disassembled Grand Grimoire, a Satanic book which he can use to undo all of Creation and for which the Devil will reward him with untold powers. In the 17th century he escapes from a witch hunter into the future 20th century to complete his task. After being taken care of by a friendly housekeeper upon his arrival, he chops off the man's fingers and bites out his tongue to kill him. He uses an unwitting medium to channel his master and then carves out her eyes to use as a compass. He further casts a Rapid Aging curse on the heroine to extend her suffering by seeing her own life go by in a matter of days, skins a child and boils it down for the fat so he can use it in a flying spell, and threatens to kill a priest's unborn children to compel him to provide the location of the last pages of the Grimoire.
Evil Is Sexy: The Warlock's good looks tend to be commented upon, and he uses that to his advantage.
Family-Unfriendly Aesop: This film features a very disturbing way of showing kids just why they should never talk to strangers.
"Funny Aneurysm" Moment: Post-9/11, Redferne being able to get past airport security and onto a plane carrying a four-foot-long, sharp-tipped, wrought iron weather vane becomes less funny.
Nightmare Fuel: Particularly nice example of this is a scene in the third film, where Ashley Laurance's character is in front of a mirror, and turns around... her reflection doesn't, and starts silently screaming.
Special Effect Failure: While the practical effects in the second film are actually well done (the birthing scene for example), the visual effects are just horrible (the flying knife is the worst offender).