Captain Magenta and the rocket labelling shows that the rocket going to the Moon is an XK3, but the pilot calls it XK5
Green and Scarlets seat belts change colour between shots on the way to Crater 101.

When Scarlet, Blue and Green arrive on Lunarville 7, SID identifies them through the badges they're wearing. However, when Scarlet switches badges with the Lunar Controller, SID still recognises him as Scarlet (when they arrive back at Lunarville). Surely when he said 'Captain Scarlet, Captain Blue and Lt. Green have arrived in Docking Port 3' he should have said 'Lunar Controller, Blue and Green have arrived'.
Plus, according to SID (I think - he was impossible to understand) the rocket was at Docking Port 3 - although when the Moonmobile docked there I didn't see a rocket in the same place.
And finally (but this isn't their fault) the Lunar Controller said man landed on the moon in the 70's... oops

I wonder if the later sci-fi series UFO pinched the idea for SID from this episode?

Did anyone else half expect that when SID got shot up and started repeating itself, it would eventually start singing "Daisy, Daisy"? ;-)

Er.....
Hmm.....
Let's see....
No.

But UFO definitely stole the idea of the Moon mobiles from this ep.

Since UFO was from the same team (more or less), surely they "used" the idea as opposed to stealing it!

Well, whatever.
Do you wish for me to make the noise of a frightened hippo for you? I can do it very well y'know...

I am sorry, but what's that got to do with Lunarville 7?

Well, whats Lunarville 7 got to do with frightened hippos? Its a double-edged sword y'know.

The Controller asks Orson for details on how Spectrum got a Moonmobile, Orson begins to explain, and the Controller says he's not interested in explanations!

I loved the scene with the bug--Scarlet cups it in his hand, silencing it, and after Orson turns the sound up, Scarlet bellows into the bug. A nice touch of whimsy, considering that Scarlet could have simply broken the bug.

When they spoke of their belief that the Lunar Controller was a Mysteron, and wished that they could check him with a detector, Captain Scarlet said "We never would have been allowed to land with one." How would the Moon personnel have known that they were carrying one before they landed? For that matter, why didn't Captain Blue suggest that Scarlet walk up close to the the Lunar Controller and see how he felt?

Where were all the Moon personnel prior to the emergency evacuation? It would have been interesting to see how the unchanged personnel felt about the Lunar Controller's actions.

How did they program those recognition discs? Orson handed them three discs, that appeared to be identical. Shouldn't they have needed to individually identify themselves to SID so that it would know who was whom?

Having the color of Captain Scarlet's and Lt. Green's seat belts switch around was odd enough, but why were all the seat belts colored differently in the first place? Why not all the same?

Considering how rough the surface of the Moon is, was that Moonmobile really that practical? What if one of its legs went into a hole as it came down?

Having the Lunar Controller threaten SID with a gun at the end, as though it was a sentient entity, was rather ludicrous. Come to think of it, why hadn't the Controller already discovered on his own that his disc wasn't working properly?

It had enough legs, it can afford to lose one.