The cross-cutting to the Doctor fighting the giant birds in the first episode was funny, and it let the Brigadier and Jo have a more active role than what we're used to seeing. This is easily the best Doctor outfit to grace the screen throughout the show's history, and the hot pink acrylic gyroscope was a pretty nifty piece of set dressing; overall the colours in this serial are gorge.

I don't usually like when they palm off a long-running female companion by giving her a man to fawn over (especially if he keeps calling her kid and tells her that they're getting married after a few days), so at least here there's an added factor of adventure, that she wants to go to the Amazon because of her interest in funghi. It's also a bit depressing that this story of anti-pollution, renewable energy, and high-protein meat alternatives was broadcast in 1973, given the current state of affairs. The Brigadier bonding with the science hippies was really fun though; this serial as a whole has good humour.

The self-termination of Ralph Fell was quite striking to me, I think because even the villainous Stevens treated it with solemnity. Because the deaths are one by one, maybe they feel more grounded and drawn out, to the point where I'm rooting for each inflicted person to survive, even if I know that they won't.