'The Two Doctors' provokes a fairly lukewarm response from many fans, for a variety of reasons including the relatively high level of gore and violence on display. Given that Robert Holmes is by far my favourite Doctor Who writer, I must concede that it is rather disappointing; nevertheless, despite many flaws, it has much to offer and is arguably the best multi-Doctor story of the entire television series.
There are several problems with 'The Two Doctors'. The most obvious is a rather gaping plot hole, which is the fact that the Sixth Doctor has no memory of the events taking place, despite the fact that he meets his Second incarnation here. This is arguably a problem with both 'The Three Doctors' and 'The Five Doctors', but is less obvious in those stories. In the former, the Time Lords deliberately cause the first three Doctors to meet, and the casual reviewer is reminded at the end of that story that they are capable of blocking memories (a fact first established in 'The War Games') as they restore the Doctor's memory of how to operate the TARDIS at the end. 'The Five Doctors' is less blatant, but the line "Old Rassilon is very clever" covers a multitude of sins. Here, there is no explanation at all for why the Sixth Doctor does not remember these events; whilst I can quite happily sit back and espouse the virtues of the "Season 6B theory" (which also, incidentally, explains the continuity problems for which this story is notorious amongst fans), the casual viewer should not have to resort to complex theories in order to explain the plot. The reason provided for the Doctors meeting each other is that the Sixth Doctor feels the trauma suffered by his past self, but this provides yet another logistical nightmare; unless the off-screen interference of the Time Lords in sending the Second Doctor to visit Dastari causes a change in the Doctor's timeline, it is akin to me feeling the trauma of some childhood injury, and if some change to the Doctor's timeline has occurred it raises the question of why only the Sixth Doctor goes in search of his past self. Neither explanation is at all logical.
But despite this, I maintain that 'The Two Doctors' is the best multi-Doctor story of the television series, for the simple reason that the Doctor essentially bumps into himself on his travels. This isn't implausible for a time traveler, and I find the concept far more appealing than multiple Doctors being plucked out of time deliberately in order to combat some threat. Furthermore, of the three multi-Doctor stories in which he appears, 'The Two Doctors' boasts Patrick Troughton's best performance. He still doesn't quite recapture the fierce intelligence, compassion and whimsy that he brought to the role during his own era, but he's a lot better than the caricature of 'The Three Doctors' and 'The Five Doctors'. He also works well with Colin Baker, the pair complementing each other nicely without the rather contrived on-screen bickering that twice previously has characterised Troughton's appearances with Jon Pertwee. The Second and Sixth Doctors do bicker, but it feels far more natural and casual than that between the Second and Third Doctors. In addition, both Troughton and Baker seem to be enjoying themselves; Troughton is clearly pleased to be back in the role as a one off, and Baker has by now settled down somewhat in the role. Actually, it might be fairer to say that script-editor Eric Saward has allowed the Sixth Doctor to settle down. He's still egotistical, arrogant and temperamental, and he still argues with Peri a lot, but he's far less belligerent than in his first two stories, maintaining the more commanding and likeable persona of 'Vengeance on Varos' and 'The Mark of the Rani'.
'The Two Doctors' however, has other flaws. I haven't mentioned the forty-five minute episode format thus far, but it has a major limitation; with more time to fill before the first cliffhanger, the writers tend to prevaricate somewhat, with the Doctor taking a good twenty-five minutes or so to get involved in the action. 'Attack of the Cybermen' committed far worse crimes, 'Vengeance on Varos' made use of its grotesque supporting characters to distract from this problem, and 'The Mark of the Rani' avoided it altogether, but Episode One of 'The Two Doctors' does rather drag. After the Sontarans attack the station, we see little of the Second Doctor until the following episode, and the Sixth spends a great deal of time wandering about and achieving little. Whilst he tracks his former self to Space Station Chimera, he doesn't really find out what is going on until Episode Two, once he finds and calms Jamie. Meanwhile, he and Peri face some mediocre traps provided by the station computer, and then clamber about in a cheap and nasty jungle-gym set until the cliffhanger.
Another problem of 'The Two Doctors' is the famously flat direction from the often-pedestrian Peter Moffatt. The ill judged long-shot revelation of the Sontarans has been well discussed, but the whole production is directed with very little flair. The overseas location filming is a waste of time and money, since little of Seville is actually seen on screen, creating the impression that the production team just fancied a holiday at the license payers' expense. Peter Howell's incidental score at least is very effective, but the overall quality of the production is highly variable; the Sontarans look absolutely dreadful, which is appalling considering how good Linx looked some twelve years earlier. Here, the Sontaran masks are rubbery and poorly fitted to the actors, and it doesn't help that Clinton Greyn's largely vocal performance as Stike is unconvincing and melodramatic. Greyn is not the only actor lacking; Lawrence Payne is terribly wooden as Dastari, despite far more successful performances in the series during the past, as Johnny Ringo in 'The Gunfighters' and as Morix in 'The Leisure Hive'. It perhaps doesn't help that Holmes' skill at characterisation deserts him on this specific occasion, since Dastari's motivation is highly unconvincing. From an old friend of the Doctor, he switches to an immoral excuser of his greatest creation's atrocities, failing to bat an eyelid at the slaughter of his colleagues on board Chimera. He equally unconvincingly sees the folly of his actions when he witnesses Chessene giving in to her Androgum nature and licking the Doctor's blood. Perhaps Dastari is just mad; this might explain why he leaves the keys stupidly near to the two Doctors after he chains them up in Episode Three
Finally, Jacqueline Pearce is unremarkable as Chessene; she basically delivers the same performance she usually gives as Servalan in Blake's 7, but without the flirting. Whilst Holmes' use of a female principle villain is long overdue, it doesn't help that Chessene is by far the least interesting villain of the piece; like Servalan, she is ruthless, intelligent and utterly untrustworthy, but unlike Servalan she lacks character. Fortunately however, there is another villain present in 'The Two Doctors' who more than compensates
Shockeye is a great villain. Whilst Holmes' skill at characterisation deserts him for Dastari, it serves him well in the case of John Stratton's cuisine obsessed villain. Shockeye is so memorable because he has an unusual but consistent and interesting motivation; his all-consuming interest in food makes him extremely dangerous to everybody else, especially humans, or as he calls them "tellurians". Typically for Holmes, Androgum culture is well thought out, making Shockeye and by extension all of his species except for the augmented Chessene a detailed alien race, rather than merely a monster. The Androgum philosophy that "the gratification of pleasure is the sole motive for action" tells the viewer a great deal about them and clearly motivates Shockeye (and their clan system, with names such as the Quancine Grig and the Franzine Grig, is further attention to detail). References to blood ties, and other cultural traditions such as tasting the raw flesh of any animal they eat before starting to cook it provide a wealth of information without the need for crass expository dialogue. The fawning Shockeye is especially effective thanks to John Stratton's performance; he captures not only Shockeye's insatiable appetite for food, but also his obsequiousness and most importantly the fact that the character is extremely dangerous. It is this latter character trait that provides most of the controversy surrounding 'The Two Doctors'. Many fans in my opinion exaggerate out of all proportion the scene in which he bites a chunk out of rat, but then I just find it amusing. Perhaps more valid a criticism is that the murder of Oscar is rather too brutal a scene for a series once more broadcast in its traditional Saturday teatime slot, as the camera lingers on Oscar's staring corpse for far longer than it needs to. On the other hand, from my perspective as an adult watching the story on video, it works because after the highly entertaining scenes in which the semi-Androgum Second Doctor and Shockeye gorge themselves on a vast amount of food it suddenly reminds us that Shockeye can and will kill without compunction. His pursuit of Peri at the end of Episode Two is highly disturbing, because rather than fawning over her as Sharaz Jek did (itself rendered effectively disturbing), his desire for her is perhaps even more horrific, as he intends to butcher and eat her. All of which brings me to Shockeye's death, and the Sixth Doctor's use of cyanide to dispatch his foe; I have no problem with it whatsoever. The wounded limping Doctor is being hunted by a physically stronger being that is both able and determined to kill him and he deals with him using the only weapon that he has to hand; the Doctor improvising to bring about the defeat or demise of his opponent is not new to Doctor Who by this time.
The Sontarans' also benefit from their creator's touch, even if they are poorly acted and presented on screen. Holmes' once more imbues them with a sense of brutal honour, Stike fretting about not being able to stand shoulder to shoulder with his men in battle due to the delays caused by Chessene. He vows that "When I die it will be with my comrades at the front", bemoans his need to rely on civilians, and general demonstrates the brutal cunning and resourcefulness that the Sontarans possess at their best. Failed thespian, moth collector and temporary restaurant manager Oscar Botcherby, who is very well written but sadly underused, also exemplifies Holmes' skill at characterisation. The sheer number of characters already vying for time in the story means that Oscar is sidelined until his unfortunate demise, although Holmes succeeds in making him likeable enough that his death really has an impact. James Saxon is perfect in the role, and had the character had more to do and more screen time, I can't help thinking that he might be as fondly remembered as such Holmes' creations as Jago and Litefoot.
The regulars are generally well served by the script. I've already discussed the Doctors, but Peri gets plenty to do with surprisingly little whining, as she is called upon to visit the villa, resulting in her near-consumption by Shockeye. Jamie is also used well, Frazer Hines falling back into his old role with consummate ease. The briefly black-and-white scene at the very beginning of the story perfectly captures the old relationship between the Second Doctor and Jamie, and Holmes further builds upon this by allowing him to bond with the Sixth Doctor and Peri too. There is also plenty of gentle wit, including Jamie's obvious hope for a farewell kiss from Anita; disappointed, he makes sure that he gets one from Peri at the end. The Sixth Doctor's complaining about himself also works quite well, and there is also a superb moment when Oscar mistakes him for a policeman. He tells the Doctor, "I can see by your raiment that you are plain clothes division", prompting the Doctor to look down at his garish clothing in puzzlement... Overall then, 'The Two Doctors' is not the classic that it could have been, but it is far better than some fans suggest.