When watching a show such as this, it is important to remember that one is looking back over 40 years – and that a lot has happened in that 40 years in terms of ideas, pop culture, film, and other such media that makes ideas and plots more common or more accessible. This thought occurred to me as I watched this serial because it involves a miniaturized zoo of real creatures, all contained within replicas of their own world and in some sort of time-loop whereby their lives are played out consistently for the amusement of whomever happens to be watching. It is such a smart and interesting idea and it is to the show's credit that it remains that way so many decades later.
The delivery of the idea of course involves monsters, races against the odds, and the usual dangers that make up the serial, but at only 4 episodes long it keeps it tight and trim, making the delivery of the narrative mostly good. I say mostly because the framing of these ideas occurs on a planet where two gaudily dressed circus masters try to sell their wares to a bunch of aliens in grey make-up (mostly). Their plot involves one of their number plotting a power move while the rest seem tied up with administrative matters. This is the aspect of the serial that is not so good, and unfortunately it is the aspect that starts to be the main one as we move on. It is an odd mix of comedy, flamboyance, and yet also driving a dramatic plot. I'm not sure it works.
I'm also not sure about the cast involved in it either. The main cast are good in terms of Pertwee and Grant (who I am starting to warm to now – which usually means she be dropped soon). The rest are a mixed bag, some playing well for laughs but not able to balance it with anything else, while conversely some play it very serious thinking they are in a different story perhaps. Either way, mostly they work as performances as required. As a serial I did enjoy Carnival of Monsters; it had a base of good ideas and imagination, it is just a shame that some of the framing elements were not as sharp as they needed to be, because it did rather weaken the whole.