Twilight of the Gods (which I should also note is my 18th book of this month) seemed a bit clunky in places and seemed to take forever to read but is basically OK (which was essentially my assessment of Bulis' First Doctor novels too). I liked the battle of the two ideological human factions over the resources of Vortis (and note that several other reviewers are too young to realise that it's a reference to Cold War turf fights in Africa and Latin America). I think he also draws quite consciously from several elements of the 1996 Annual stories - the colonisers from offworld and movable planet Vortis in "The Lair of Zarbi Supremo", and the huge intruders of "The Lost Ones" (though Bulis' aliens are a lot bigger than the Atlanteans of 1966, and remind me a bit of some of Isaac Asimov's creations). It is also, I now realise, the adventure on Voris referred to in The Dark Path. The characterisation of the Doctor, Jamie, and Victoria is pretty satisfactory, but the pace, as I said, is a bit slow.
Return to the Web Planet, which is a one-disc special released by Big Finish just over a year ago, takes Five and Nyssa back to Vortis to help the Menoptera scientist Acheron and his daughter Hedyla to deal with mysterious goings-on among the local Zarbi herds. This turns out to be due to a human intervention, whose details I found rather implausible even by Who standards, but the acting and soundscape - especially the soundscape! - help carry it off successfully.