Apparently, I live in some kind of "fanboy cave"!
I had never heard that this story was so badly scoffed by fandomn. That it's considered one of Tom Baker's worst. To be held in the same (low) esteem as, say, "Revenge of the Cybermen" or "The Android Invasion". Up until I read some of the reviews on this site just a few moments ago, I had always been under the impression that this was regarded by general fandomn as an enjoyable little yarn that is marred chiefly by the fact that it relies too heavily on C.S.O. during the second half of its telling.
But now I'm reading differently. Complaints about preposterous plotting and wooden characterisations are be bandied about by the lot of you. My big question is: what Tom Baker stories don't have some of this going on? Particularly in this era of the series!
The nice thing about Undeworld is that it does really keep these sort of problems down to the barest of minimums. With lots of free reign being given to Tom to spice up some of the somewhat more mundane elements of the story. His energy levels during the entire plot are fantastic, as he bounds about through tunnels and spaceships spreading that inimitable chaos his character is so fond of generating. He's very fun to watch throughout these episodes - whilst still not going too far "over the top" as he did sometimes in later adventures that have become notorious in this producer's run. So that, as boundless as Baker's energy seems, it does not cause damage to the storyline's credibility. The main focus is still the desire to tell an exciting adventure story. Not watch Tom Baker muck about on strange-looking sets whilst taking the piss out of bug-eyed monsters. And it's nice to see how nice of a balance Underworld draws with this element.
Underworld's biggest flaw lies, of course, in its flatness. Not just due to the C.S.O. but also some of the elements of the story itself. We have, at least, two plot elements that have, by this point, been done several times over in the show's history (attempts to preserve a race bank and a megalomaniac computer). So this immediately makes it a bit more difficult for the viewer to get all that interested in what's happening sometimes. It is always easier to get involved with a story when its premises seem "new" to us. And a good two-thirds of this story, purely from the standpoint of the series itself, is a bit of a re-hash. Even the Doctor identifies the Oracle for what it is quite quickly and almost seems to act like he's used to dealing with this sort of thing. Which, by this point, he is.
Personally, I found the scenes with the Oracle to be a bit on the tedious side because of it. In fact, it almost gives us a bit of an anticlimax to find out the Oracle is just another computer gone mad. Might have been a great twist if it had been a whole "Wizard of Oz moment" and we discovered some Minyan hiding behind the curtains who had somehow gotten his hands on a regenerator and was sustaining himself indefinitely with it whilst controlling his little underground society with an iron fist.
No such luck. Just another damned crazy computer instead. One that is nowhere near as interesting as the BOSS or Xoannon was before it. Or even WOTAN for that matter!
Adding to this story's flatness is the actual sense of integrity the director is trying to maintain with themes of the script. We have a tired and listless ship crew that is so run-down that they actually long for their quest to become impossible so that they can finally quit it (note how Jackson actually seems to cheer up when the drive crystal breaks). And a tired and listless slave society that can see no real means of finding freedom from the tyranny that oppresses it. Admittedly, all this tiredness and listlessness, as intentional as it may have been, does make it hard for the viewer to care about much of what it is going on in the story. Perhaps the director should have been more careful with how he was portraying these elements. But that is, admittedly, a tough call to make. You want to stay true to a script, but you also have to keep overall entertainment impact in mind too. And, unfortunately, that balance seems a bit "off" in this element of the story. Thus making it difficult to become all that emotionally involved with some of the storyline.
But aside from those two problems and the actual genuine "flatness" of the C.S.O., I feel Underworld has a lot to be proud of. On the more superficial side, we have some of the best model work and laser battles the series has ever produced (shield guns are, easily, one of the coolest hand-weapons ever devised on the show). On the "deeper" side of things, we have a story that not only borrows from classical greek mythology - but does so without being too blatant about it. Something "Horns Of Nimon" and a few other Who stories like it that were "inspired by other sources" could learn a lot from. The little afterthought the Doctor has with Leela back in the console room after the adventure is over wraps up the whole idea quite nicely and gives us some nice abstract philosophy to ponder over.
We also get, in amongst some of the afore-mentionned re-hashing, some really creative ideas too. Particularly the concept of a planet that is forming around a spaceship. And though some of the science regarding this idea is a bit "wobbly" (again, "wobbly science" is nothing new to Who and I'm still amazed at the fans who feel such tremendous need to pick it apart), it still made for some very imaginative moments. Of particular charm, of course, was the whole "descending down the tree of life" sequence. With its cute little lift music and, of course, yet more C.S.O!
So, in the final analysis, "Underworld" does have a few big problems to it. But I'd hardly label it a "stinker". I would even go so far to say that as an action/adventure tale, it excels in the way it was executed. And considering the way action elements in Who have oftentimes been a total travesty, that makes this particular story extra noteworthy. "Underworld" on a rainy afternoon with nothing to do, makes for a very fun viewing.