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.
YMMV: The Pirates of Dark Water
Animation Age Ghetto: A definite attempt to work around this. In the end it was killed more by the production costs (compared to the income it was getting) than by breaking the "for kids" rule.
As for the age perception, it was noted for really managing to work around this - it was still quite kid-friendly but was way more complicated than other shows of its time, with a Myth Arc.
Complete Monster: The being behind the titular 'Dark Water', a menacing oily substance that devours whatever it touches and is spreading all throughout the world. By proxy, the Dweller is responsible for countless deaths of places that the Dark Water has devoured. The Dark Dweller is the true Big Bad of the story, a being focused on domination and destruction who plans to unleash its Dark Water throughout the world, focused only on consuming and controlling what it can.
"Funny Aneurysm" Moment: Niddler's obsession with food and his cowardice both become a lot less comical when you recall he's a member of a slave race who was sold to Bloth of all people. Starvation was clearly a big part of his life before Ren rescued him, and courage likely wasn't rewarded by either the slavers who raised him or the Maelstrom's crew...
Ho Yay: young and (as much as we can tell) pretty Tula runs about with a bare midriff among seamen and the only one who really takes notice of her is Bloth of all people. Ren seems pretty comatose when it comes to the opposite sex and while Ioz does mention that he enjoys women, he keeps grabbing and hugging Ren by the waist. Also, Ioz and Zooley are pretty shippable.
Nightmare Fuel: It's never pretty when Dark Water gets a hold of anything or anyone. In one episode, one drop consumed someone from the inside out.
The Constrictus isn't particularly pretty either. And Bloth is bound to cause sleepless nights for anyone who stares at his face too long (i.e. any length of time).
Opening of episode four. Skulls and bones and creepy ship and carnivorous dragons...
Ren's eyes NEVER move. Although that may be more Uncanny Valley. Especially since half the time he's looking at the screen head on when there's no way he should be able to...
Squick: In A Drop of Darkness Cray is insistent on marrying Ren while calling him Primus. A whole new level is taken when considering that earlier in the episode Cray muses that Ren might have been her son.
And any of Bloth's crew. Scratch that. Any bad guy. Konk can fit his entire hand up to the wrist in his giant maw. And does.
Villain Decay: In the miniseries, Konk is a very capable bad guy saddled with incompetent minions, capable of giving the heroes a difficult time on his own. He is later downgraded to being an incompetent minion himself.