Roots: Pulp Fiction (out-of-sequence storytelling), Star Trek: Voyager's episode 'Juggernaught' (a race with huge leaking garbage ships), Twilight Zone's 'Eye of the Beholder', Buck Rogers in the 25th Century's 'The Dorian Secret'. On approaching the Koteem base the Doctor remarks "Spiders, flies and parlours come to mind"
Dialogue Triumphs: "Always a mistake, in my opinion, working for a more technologically-advanced species"
"Confusing, isn't it, when you don't know who the bad guys are? So much simpler when they have a satanic beard or black ears."
"Sometimes if you stare at a painting for too long and for too close, all you can see are the brush strokes. The more formless and more meaningless it seems to become"
Dialogue Disasters: 'Do you know what they do to beautiful boo boos like you in the penitentiary?'
Double Entendres: 'What exactly is going on here?'
Continuity: The planet Veln is, presumably, the only inhabited world in its system, and is named after its population which has been measured for around eight centuries. Veln appear to have an equivalent lifespan to modern humans, with each generation lasting around twenty-five years. Most Velns can't breathe the atmosphere for a prolonged time without a pollution mask. The pollution has caused a genetic disfigurement, and only the richer Veln can afford to use surgery to render themselves beautiful. The Veln are familiar with the idea of alien life, but are not yet technologically advanced enough for interplanetary travel (they have orbital platforms but are merely 'on the brink' of exploration) and seem to know only of the Koteem through the aftermath of the catastrophe.
The Koteem are an arthropod race from just past Andromeda, with five or six eyes (it varies from continent to continent). They can create simulacrums that look Veln and can contain Koteem essence. They are not aware of Traken or Gallifrey.
The Koteem used the highly toxic and mutagenic substance diestrium as a source of energy, discovering too late its effects. In an attempt to save money, a Koteem waste disposal ship detoured near Veln, then a forbidden planet. There, in high orbit, it ventured into the TARDIS' warp distortion field (the Doctor had effected a materialisation for running repairs) causing the ship's diestrium waste to spill out onto the planet. As a result the Veln world was ravaged by ecological disaster and economic and social collapse. Koteem estimates suggest that the Veln, now four generations into a mutated gene pool, will be a dead species within four generations. The Doctor postulates that the diestrium could be counteracted with the ionisation of hydrogen (it's a shame he never tells anyone this!)
There is a Galactic Central Council. Resolution 441 forbids space travel around the veln planet; post-catastrophe Koteem presence in Veln space was declared illegal, leading them to resort to clandestine attempts at reparation. To this end, a small Koteem faction sacrificed themselves to combine their essences with that of the Velns, to enable them to be combined into a new, 'beautiful' hybrid race.
The TARDIS outer shell can be affected by diestrial pollution (it spreads to the Ship's power relays.) It can self-regenerate relatively quickly, but needs the odd nudge along. It emits a warp distortion field.
Nyssa doesn't smoke.
The Doctor is carrying a pair of binoculars.
Untelevised Stories: The (Fourth?) Doctor and Sarah encountered Koteem at a conference, including one with seven eyes.
Location: Veln, and Veln a century later.
Links: The Land of the Dead ('like being back in Alaska.'), 'The Ark in Space' (Helmic Regulator) The Doctor's mention of "satanic beards" and "black ears" is a nod to the Master (probably) and the Cybermen.
Bottom Line: "It's all a question of perspective"
A well-crafted and economical exercise from Big Finish's earliest 'experimental' period (see also: A Natural History of Fear and Doctor Who and the Pirates) The problem with this disjointed story construction is that by the time episode four rolls around, the audience is just waiting for the story to fill in the gaps and knows exactly what is going to happen, which does rather kill any sense of expectation of development. That said, the final twist in the role the Doctor has in unwittingly starting events, brings a nihilistic tone to the overall story. One of Briggs' best.