If the cliffhanger to Episode Three wasn't odd enough (Lady Adrasta is threatened by the monster. Will the evil villainess escape? Or will The Doctor win yet again?), the main villain of the piece, Adrasta, is killed seven minutes into the episode, removing any sort of conflict for the duration of the story (as well as killing off just about the sexiest tyrant the series has ever seen).
Adrasta's death not only removes any conflict (Karela's meek alliance with the ineffectual throng of bandits was never going to go anywhere, especially with Torvin as the bandits' leader), but it also sucks any possible drama out of the last few minutes, leaving The Doctor to perform some pseudoscience solution to the suddenly new problem of a neutron star coming to destroy Chloris.
So, when you add it up - ludicrous characters, ridiculous monster, bizarre plot resolution - this should be one of the worst stories ever made. And yet, The Creature From The Pit seems to succeed despite the massive number of negative aspects working against it simply because, like much of Season 17, this story is a great deal of fun to watch. The Creature From The Pit is bad, but it is no means unwatchable. It probably comes across better when viewed in quick succession, though. I can't imagine Creature being one of only six (later five) stories offered during a particular season of Doctor Who, but it works perfectly fine as a nice romp in the midst of...well, slightly less rompy stories (and I do mean slightly. Stay tuned.).