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.
Complete Monster: The High Priest Drwc. He convinces Rhiannon to become Arawn's sacrifice by threatening to chop off a little girl's fingers. There's also that whole "I want to summon a demon king to destroy the world so I can rule what's left" thing.
Myrddin is more of an Expy of Greek Titan Prometheus and has nothing in common with his Welsh namesake. The villains feel like a Gnostic Demiurge committee, being tasked by an aloof deity to create the world but failing at making it `perfect`... and are not happy about it.
Fan-Preferred Couple: There are a lot of Arthur x Octavia shippers possibly because their Distaff Counterparts to each other (eg. Both are skill swordsmen, kind to children, lost a family member when they were younger, a leader who cares for their troops and grew to hate and later respecting each other.).
Ho Yay: Arawn, to both his mentor Pwyll and his apprentice Arthur. To a lesser extent, Decimus towards Gaius via Subordinate Excuse. One one hand, deep camaraderie and eternal loyalty; on the other... somewhere between Arawn and Pwyll's nigh-instant Heterosexual Life-Partners status and Arawn hallucinating Pwyll before he resolves into Arthur and spurs Arawn to stop dying...
Les Yay: Though merely really good friends in the game, that friendship necklace Octavia gave Morgan in the anime might make one think otherwise. And the holding hands, and Octavia's revealing Foe Yay...
Narm: The English version of the original game's theme plays at certain points in the story - usually those where you would not want to be distracted by its questionable quality.
The English dub of the anime is pretty good, but the Gael characters have Irish accents that range from subtle, nuanced, and believable to MAGICALLY DELICIOUS.
No Export for You: Not the anime series thankfully, but the game probably won't be released in the US.
This is surprising...since the SEQUEL was released.