'Revenge' of the Cybermen? Ugh, here we start the Cybermen descending into emotive behaviour. While entertaining, David Banks' cyberleader frequently showed too much relish for an unemotional being. Here they crack the odd joke (the cyberleader comments when tying the Doctor up on the Beacon that he won't be around to see the 'magnificent spectacle' of the crash with Voga) and a bit of monologuing about the destruction of Voga ending with "This is good!". The cybermen are restyled from the Invasion cybermen with more pipes and flares (it was the 70s).
Something about it all seems a bit lacklustre. Kellman is a great villain, he sort of comes out on the good side working for the Vogons, but still murdered a lot of people. I can't help wondering why his plan needed to be quite this ruthless, but he was going to help the Vogons blow the Beacon up anyway. The location shooting looks great, the main cast all come out of it well. The ark looks a bit cheaper this time around but the caves of Voga are much richer being filmed at Wookey Hole. It's probably just that the Cybermen are so naff reduced to just a few men with a silly scheme. The Vogon plan doesn't seem so smart either. There's a lot of things that don't add up, such as the Beacon not being able to radio for any help, the transmat removing the cybermat 'plague' by being set up for human tissue, but transporting the Doctor, Cybermen and their cloths and other non-human tissue. The surface of Voga as the Beacon flies over is obviously a revolving log in front of the camera and isn't well realised. The Cybermen fall for the old 'tie them up and leave them to die' trick which has been old since moustache twirling villains tied women to railway tracks. It makes no sense for the Cybermen to do this unless they bizarrely relish imaging the Doctor and Sarah having the front seat for the collision of the Beacon with Voga.
This story is the first to introduce the cyber-weakness to gold, yet oddly enough the only cybermen to die from gold is that injected by the captured cybermat. A cybermat is disabled with gold dust but the Doctor quickly gets it working again to terrorise Kellman. Both occasions when the Doctor tackles cybermen with a handful of dust they he is beaten back, people just can't get the opportunity to use it effectively as a weapon. While being a weakness, it's not an entirely practical one to exploit. Also we can assume that only gold dust is effective, as Vogon bullets are undoubtedly made of gold yet are ineffective. Either the gold needs to be a dust or the gold bullets, like regular bullets, just bounce off. I'm guessing both are true. But compare to Silver Nemesis where anything made of gold cuts through the cybermen like a hot knife through butter. Bullets are ineffective but gold tipped arrows and coins fired from a catapult cut them down. As soon as gold penetrates their armour they die, no talk of "clogging their respiratory systems", it's more like a puncture wound from gold is akin to blood poisoning from a lethal snakebite. Maybe gold in contact with the coolant circulating within a cyberman is lethal, but ultimately you have to ask why?? It's an inert metal.
It's a shame that Tom Baker only met the Cybermen once, and Pertwee only in the Five Doctors. The gap between the Invasion and Earthshock seems a long one with only this unsatisfying morsel in the middle. Hard to imagine now, what with the Daleks appearing in every season of Doctor Who, that you could go for years without these 'regular' monsters. People criticised the 80s for being continuity laden, probably with the nadir being Attack of the Cybermen, but throughout the 70s the old series was braver than the new by constantly creating new stories and pushing the horror to the limit. Currently the New Series relies on its past a lot more than is generally admitted with the Daleks appearing more frequently than ever over the last 6 years, and plays it quite safe regarding horror as seems in line with BBC paranoia regarding receiving complaints on any matter.