Roots: Paradise Lost, Chorlton and the Wheelies (Sabian's Charleston malapropism), Batman the TV series ('atomic batteries to power, turbines to speed') and 'Jabberwocky' from Through the Looking Glass (the Doctor finds the 'gyring gimble'). Not surprisingly, many Biblical parallels abound, including Kwundar's inversion of Christ's teaching ('impose your will upon others, lest they impose their will upon you'), and the mediaeval notion of Hell being an inversion of the world (Sabian and Anona are the same age and both 'apprentices', yet operate in opposing ends; their training is a deliberate contrast - as Sabian is taught to Charleston, Anona is trained in combat). Anona paraphrases from the book of Ruth: ('where you lead, I will follow'), and Shayla from Romans ('the wages of sin'). Kwundar's name, when rearranged phonetically, is 'dark one'; the awesome power of his visage recalls that of Jehovah's in Exodus. Lost in Space ('Evil knows evil.'). Narthex paraphrases General Patton ('The idea isn't to die for our ideals, but to make the enemy die for theirs').
Fluffs: The Doctor and Shayla are trapped 'quayter the merchant ship' according to the soldier, later (the same one?) claims to Narthex that 'we have secured this whole sexer'
Goofs: Kwundar can look through time and space yet can't see that he will fail [even after looking in the Doctor's mind and seeing Traken being later destroyed - is he unable to see his own fate?]
The sound of the gun being taken apart sounds like a pottery vase breaking [perhaps it's ceramic?].
Technobabble: The hatch has a neutronic lock, which has fourteen trillion possible combinations (the Doctor's sonic screwdriver could have made short work of it, alas).
Dialogue Disasters: "You can feel me in your mitochondria."
Dialogue Triumphs: 'Then the Doctor is dead?' 'Well, the screaming's stopped...'
'You're one of those people whose glass is always half empty, aren't you?'
'The mark of a gentleman is that he knows how to Charleston but doesn't.'
The Doctor indulges in schadenfreude: 'Hello consul Janneus, consul Hyrca. You've got matching chains...'
Kwundar and the Doctor: 'Don't turn around-' 'I'm not frightened of you-' '-no, but then you haven't turned around.'
Fashion Victims: The Doctor's swimming costume. ('The Space Museum' has so much to answer for).
Continuity: During the 'primeval' times, before the Keepers arose to control the Source, Trakenites are especially superstitious regarding evil, seeing it as a cancer [the existence of fosters isn't a contradiction of this, merely another suggestion that to the planet's population 'alien' and 'evil' go hand in hand. They do, however, have a spaceport and trade with other worlds]. Though they have no gods, they revere the Source, an avatar of the original sentient sun, constructed under the inspiration of their once 'living god' Kwundar 2532 years previously. The Source regulates the climate, imposes judgement upon its population and provides energy for the planet, 'burning' those who might do ill within the Union. Due to the presence of the source, Traken psychic defenses have been rendered unneccessary and so have decayed from lack of use. The Doctor can teach Nyssa some new defenses, but only away from the Source's influence.
Kwundar uses his mental ability to detect spacecraft coming and going. Such a thing is possible, but very rare. Before Kwundar is destroyed, he sends out a signal, a 'dinner gong' for other Primeval beings to come back into the universe, and marks the Doctor.
Shayla carries a medical computer with her wherever she goes. She was the greatest doctor Traken medicine knew, and the first [Trakenite] Keeper.
It may be inferred that Trakenites have the same, if not longer life spans than humans at this time (their measurement of generations is similar to our own - Hyrca says that the Source was created 'one hundred generations ago'). Falconian plague can be inoculated by a dose of Atolix. A tincture of liquid gallas can treat an existing case. By Nyssa's time, all disease had been eradicated.
Nyssa, like the other Trakenites, didn't learn about their history. She's never had the need to swim before. Her departure from Traken in the world's future was detected by Kwundar, whereupon he 'released her psychic potential', (hence its increase during 'Time-Flight' and preceding audio adventures).
A Crested Avar (a bird) is native to Traken. Near the consul chambers and Source are the Northern Shores (it isn't specified whether these are to a sea or a smaller body of water). Narthex's daughter studies at a school in Vizal Prime.
The Doctor carries artificial gills to aid underwater breathing. As a Time Lord he has superior psychic defenses. His doctorate isn't in theology ( although he may have picked up an honourary one in this somewhere). The Doctor knows what being knocked out feels like. He thinks he should write a paper on it.
Links: 'The Keeper of Traken', 'Black Orchid', 'Kinda', 'Earthshock' ('machine men'/Adric's death).
Location: Traken, the 'primeval era' Traken, 3000 years before its destruction. This adventure takes place "several weeks" after the events of 'Kinda'
The Bottom Line: An intriguing look into the history of a planet that, refreshingly, isn't Earth, is deftly scripted and played. Lance Parkin's script delivers more for those continuity buffs among us, but doesn't dwell too much on 'Traken' as anything more than a setting and framework for an interesting exploration of the latter story's contradictions of morality and enlightenment. All in all, understated but rather good.