As others have pointed out this is rather a standard android invasion type story with worked in rehashed pulp science fiction props and plots.
Having said that it is more of a comic horror type of story with Tom Baker literally hamming it up throughout. From the early moaning and groaning from Sarah Jane (are we there yet, are we there yet Type of complaining about getting back home) to the Marie celeste type village - could be in Epcot - through to the twisted Sontaran type aliens there is a lot of tongue in cheek humour. This also is a bit of a prototype of the later, not as good, Peter Davison story 'Four to Doomsady' which has a number of similarities but not as good sets or location.
This story is quite droll and if it was to be taken too seriously then I must admit it would not be such a good tale. I have not seen such a Doctor Who where Tom Baker is in such good comic form. It reminds me of a later UK tv show where he played a house doctor and obviously had a lot of fun doing it.
Do not judge this story too harshly. Given the context of the other stories of the season and the Tom Baker series it would not be terribly logical to broadcast a dummy.
Watch it in lightheart and you will get much enjoyment from it.
Originally broadcast 22 November to 13 December 1975.