Doctor Who: Legend of the Sea Devils would've worked better as an ordinary episode, not a special

Gizmodo

"None of it really works beyond the cursory idea that it was, ultimately, an episode of television that got made," says James Whitbrook. "There’s little build up or tension around the Sea Devils that dampens (sorry, not sorry) their threat—they appear, they say they want to take over the world to the Doctor, and then they just... kind of sit there doing that until they’re stopped. They’re great looking monsters (perhaps one of the best in Who’s recent history in terms of redesigning a familiar look) but not particularly monstrous, so there’s little of that classic fear outside of a short, sharp dose near at the start of the episode."