The aliens behind this cunning little invasion plan, the Kraals, look pretty good. However I think this is a case where in order to make the story work as it’s presented, you have to accept that Styggron just isn’t a very competent would-be world conqueror. That would explain the level of mistakes that he makes, as well as his exaggerated claims about how indestructible his androids are. He desperately wants to conquer the Earth, but he hasn’t really thought his whole plan through
There’s the germ of a good story idea here, but the script needed a bit more work I’d say. At first the deserted village and deathly silent pub patrons are nicely creepy, and the mystery is an interesting one. There’s a very retro feel to this story, possibly due to the presence of UNIT and the direction by Barry Letts. It’s just not quite as edgy as the standard Hinchcliffe/Holmes storyline. And it’s hurt by the absence of Lethbridge-Stewart, though the Brigadier is name-dropped at least. Colonel Faraday is a joke. He’s a blustering dim bulb of a military commander, and can’t be taken seriously.
Mr. Benton gets less to do than I’d like, though his appearance in the story is welcome. The most memorable scene for the character is the moment where his android double shoots the android Doctor, a rather casual bit of violence that stands out in this lighter storyline. And then there’s the scene where Benton discusses with some chagrin taking his kid sister out for dinner, which brought a smile to my face. Harry Sullivan makes his return in a small role, and his brief scene with Sarah at the end of the story brings back fond memories of the previous season. Both Harry and Benton casually appear without any fanfare, and then end their status as regular characters without even get a proper goodbye scene with the Doctor and Sarah. And we never see them again. For someone as likeable as Harry, that’s a shame. For a long-running character like Benton who’s been around since the Troughton era, it’s even more of a pity.
Overall, “The Android Invasion” is decent. It contains a reasonable story idea hampered by a weak plot. But throw in a nicely designed monster and the return of Harry and Benton, and the story remains enjoyable despite the problems.