Zagreus is surely the best (so far) of the various anniversary offerings. The Three Doctors is rather poor, The Five Doctors is at least an honest effort, and the less said about the 30th anniversary the better. But here we have the "current" Eighth Doctor/Charley pairing (the sparkling Paul McGann/India Fisher combination) meeting a whole host of characters, more or less real, played by former cast members of the televised series. I didn't recognise all the voices on first listening, partly because I wasn't expecting so many, but I may even try listening again with a crib sheet in front of me; as well as Lalla Ward and Louise Jameson reprising Romana II and Leela, with splendid Time Lady/savage bitchiness setting up the scenario for the Gallifrey spinoffs (plus John Leeson as K-9), we have the voices of Polly, the Brigadier, Sarah Jane Smith, Nyssa, Turlough, Peri, Erimem, Evelyn Smythe, Mel, Ace, Benny, and the Fifth, Sixth and Seventh Doctors all playing other parts, and also Don Warrington as Rassilon, three years before he became President of Britain. Oh, and Jon Pertwee as the Third Doctor, even though he had died seven years earlier. I'm not wild about the main plot strand, though it develops quite well from the previous Eighth Doctor story, Neverland, but the device of exploring the Doctor's past through distorted reflections in his subconscious works - it could have been really gruesome and self-indulgent, but in fact you can't wait to find out what happens next. I am not surprised to find that Alan Barnes, who is my favourite of the Big Finish writers, gets an authoring credit here.
Slipback was produced in the 18-month hiatus between Colin Baker's two full seasons, a six-part radio series starring Colin Baker and Nicola Bryant as the Sixth Doctor and Peri. It's an odd contrast to the more recent Big Finish audios featuring Baker and/or Bryant. The first difference to strike you is that Baker really doesn't much reflect the egotistical brash persona of the Sixth Doctor as seen on TV and heard in the videos. (Bryant is unmistakeably Peri though.) The second difference is that the six episodes only last ten minutes each, which really is the wrong length. If this had been successful, we might have seen a seamless transitioning of Doctor Who to audio instead of television, more than a decade before Big Finish got into it. But it wasn't. The problem is that the author was Eric Saward, trying to channel Douglas Adams and not doing it very well. One of the characters is a computer with a squeaky accent, combining Eddie and Trillian from the Hitch-Hiker's Guide. Valentine Dyall is wasted as an insane spaceship captain who enjoys his baths. The whole thing fails to gel.
None the less, this is the first "proper" Doctor Who audio play. The 1976 Fourth Doctor audios don't count: in Doctor Who and the Pescatons, most of the narrative is carried by the Fourth Doctor telling the story, with occasional voicing from Sarah Jane Smith and the villain, and in any case it isn't a "real" BBC production. Exploration Earth is too didactic to count as proper drama. The two Third Doctor audio stories were recorded later. So Slipback is in a lot of ways the fons et origo for Big Finish's subsequent triumphs.