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.
Nightmare Fuel: The Cyclops standing in the dark, where you only see his one eye. This freaked out Ergo, who then decided to join Colwyn.
When the Slayers are killed, they shriek, spark, their heads split open, and you can briefly see wet, dark red things slipping out of their skulls and burrowing into the earth...and it's never explained.
Awesome Music: The music during the scene where the group rides the Fire Mares to the Black Fortress.
James Horner's score for this film has gotten four different album releases, each one expanding on the previous one.
A crowning moment made even better by the (admittedly) AnviliciousAesop that comes with it: whenever Ergo tries to use his magic for selfish ends, or as a Baleful Polymorph to punish others, it immediately backfires on him. The only times it works as he wants are this moment, and when he provided Titch with a puppy for a while—in other words, when he was selfless.