Sir Terry occasionally would produce Travelogue Joke books, where the protagonist - most often Rincewind - would run from place to place with a gag or two played out in each place, and the places corresponding to locations, cultures, myths of genres from our world. In theory these are wrapped around other topics. Colour of Magic works because three of the four were solidly funny pastiches of specific fantasy authors. Light Fantastic stumbles because the travelogue bits aren't great and the end of the world plot feels out of place. Witches Abroad works for the travelogue because its targeting fairy tales but not for the endgame (IMO). Interesting Times' jokes on China really only land (sometimes) because they are thematically tied to the larger discussion of authoritarian governments.

That brings us to Last Continent, which is essentially "Hey, lets poke loving fun at Australia for the Australian audience" which never ties with the idea its wrapped around, which is a discussion of evolution. While the antics of the wizards in that arc are amusing they remain not my favorite group as they always feel like a set of comedy tropes that break out whenever exposed to something new. The book repeats the descriptions of that over and over, the Travelogue plot and the Wrapped plot never jell, or even come close to it, and it just doesn't stick the landing.

There are still lots of individual funny bits, but they never cohere. It reads like the funny fantasy of lesser authors from the 1980's.