What's Wrong With... The Moonbase

This is a Cyberman story, so let's start with their plan.

The Earth's weather is controlled by a gravity-influencing machine in a base on the Moon. The Cybermen intend to seize this machine - the Gravitron - and use it to wreck the climate, softening us up for an invasion. Rather than just break their way in to the base and assume control, they devise a cunning subterfuge. Clever. Clever.

Stage 1: break into the base surreptitiously, so you can sneak in and out.

Stage 2: introduce a toxin into the sugar supply. This is a special pathogen, which will leave its victims still alive but capable of having their minds controlled.

Stage 3: start sneaking the virus victims out of the sick bay one by one. Pretend to be a patient if anyone comes in, by lying under a duvet - no-one will notice.

Stage 4: take the patients to your spaceship where the mind control operation takes place.

Stage 5: once you have enough mind controlled personnel then, and only then, do you come out into the open. You only actually need one human, but kidnapping more will greatly increase your chances of being detected and stopped.

Stage 6: get your abducted human to operate the Gravitron for you, as you are somehow susceptible to gravity, despite it being a universal force.

Stage 7: create lots of hurricanes and typhoons, etc.

Stage 8: invade. Not because you want to take over the planet - more because you think humans will defeat you in the future. You know what? You're right...

It was one thing for the Cybermen to be susceptible to radiation, as in their first outing, but having problems with gravitational forces is a different matter. The writers clearly had to have them allergic to something, to explain why they don't just smash their way in on a frontal attack.

Does it matter which personnel you have selected for mind control? Apparently not. Poisoning the sugar supply is a rather random way of doing things - which might explain why it's the medic and a guy who looks after the stores who are taken, rather than any actual Gravitron personnel.

Surely a foodstuff would have been one of the very first things you would have looked at, in a case of potential poisoning - especially one not everyone uses, if not everyone is falling ill at the same time.

We see a crewmember collapse immediately after drinking some sugared coffee. If the toxin always works this fast then why didn't the crew realise that the presence of a spilled coffee cup next to each victim might be a clue as to how they poison is being spread.

Why do the Cybermen go to such lengths to avoid detection, then get spotted twice by Polly within a few minutes? The sickbay is small, so can we honestly believe that a Cyberman could hide under a duvet without someone noticing - especially once they have started removing the patients.

Surely another part of the base would make a better place to hide than the sickbay, during a health crisis when it's going to used a lot.

Despite claiming not to be a doctor of medicine since the early Hartnell era, the Doctor here thinks that he did study medicine under Lister, at Glasgow in 1888. Now, he doesn't claim to have actually passed the degree, but he couldn't have studied at this time, in this place, under Lister. Joseph Lister left Glasgow University in 1869. In 1888 he was working at University College Hospital in London.

The Cyberman plan does, initially at least, work out in their favour. However, Polly devises a weapon against the Cybermen who have taken over the base - a solvent which melts their chest units.

The Cybermen simply reactivate one their mind-controlled subjects, who have been left conveniently unguarded. One of them manages to take control of the Gravitron.

Despite their plan going smoothly, the Cybermen then decide to attack the base's dome with a laser cannon - putting their own agent out of action. All they had to do was wait for Dr Evans to wreck the Earth's surface with severe weather conditions and they would have achieved their goal.

The Cybermen then decide to smash their way in - the one thing they have gone to great lengths to avoid. By wrecking the dome, they will have killed all the humans - including their own mind-control subjects - so would have no-one to operate the Gravitron. They'd have to do it themselves.

Why did the Cybermen only fire on the dome the once? They wait ages before firing again - giving the Doctor long enough to employ the Gravitron to prevent any other strikes.

The reason the Gravitron can't be pointed along the horizon is that it would affect the base - and yet when the Doctor and Hobson do point it across the lunar surface it has no effect on the base at all. The crew don't all go floating up to the roof.

Last, but by no means least, how does Polly recognise these streamlined robots as Cybermen, after barely a glimpse. Also - where do these Cybermen come from, if we only recently saw their entire planet destroyed and their entire race wiped out. (There was a line about a new home planet of Telos, but this was cut - so there's no on screen explanation).