2|entertain DVD documentary about the nature of cliffhangers on both BBC and BBC Wales Doctor Who.
It attempted to categorise cliffhangers in various ways, and came up with examples of several main types of cliffhanger, including:
- those which reveal a monster - The Ark in Space parts 1-3, Terror of the Zygons part 1, Terror of the Vervoids part 1, Aliens of London
- those which suggest the Doctor is about to die - The Caves of Androzani parts 1 and 3, The Deadly Assassin part 3, The Ultimate Foe part 2
- those points at which the narrative completely changes track - "An Unearthly Child", The Mind Robber part 1, The Face of Evil part 3, The Curse of Fenric part 3, Bad Wolf
- those cliffhangers which "cheat" by introducing new footage into the cliffhanger reprise which suddenly gives a way out of the cliffhanger not visible in the previous episode - The Mark of the Rani part 1, Image of the Fendahl part 1, Genesis of the Daleks part 2, The Stolen Earth
- flatly rubbish cliffhangers - Dragonfire part 1, Death to the Daleks episode 3, virtually every cliffhanger during The Trial of a Time Lord — though especially Terror of the Vervoids parts 3 and 4, Snakedance part 3