Review of all 5 episodes:
This story is very similar in type to the William Hartnell era story The Celestial Toymaker (although this is quite a lot better). It is, like that story, a whimsical trip into a weird make believe world controlled by a sinister power. This idea was returned to again later in the classic series to some extent with aspects of a couple of stories (e.g. Warrior's Gate) and again in recent Moffatt/Matt Smith era series with Amy's Choice and to some extent The Doctor's Wife being derived from the same template.
The excellent first episode has a surprise element with some dramatic and brilliantly unusual happenings such as an exploding TARDIS and an endless white void. It is very well done and provides an enticing, fascinating start to the story. Then there is a thoroughly enjoyable if not quite as brilliant second episode where ideas such as the land of fiction, characters like Gulliver (speaking only lines he spoke in original text, a great idea very well executed) and a maze-like forest of words provide a good amount of interest. After that there is a still very good third episode then a slightly disappointing and occasionally silly 4th episode and a decent but rather unremarkable and not wholly successful 5th episode.
This has a disappointing lack of development after such a promising start. It must go down as a missed opportunity which would have been better as a 3-parter. Great first episode though.
My Ratings: Episode 1 - 10/10, Episode 2 - 9/10, Episode 3 - 8.5/10, Episode 4 - 6.5/10, Episode 5 - 7.5/10
