While the plot of this particular adventure is simplistic, it must be noted that Dr.Who was still intended for children at this time. The 'giant' props are very well done by Dr. Who standards and the plotline surrounding the deadly experimental insecticide is a typical example of the enviromental messages that seem to be a frequent theme of many Dr. Who episodes thought it's history.
The biggest enjoyment I got out of this episode, however, came from the fact that not only has it been over a decade since Dr. ...It was like seeing a long lost friend and ironically the chair I used to watch it in in the attic is now in my own Den at my house.
I gave this one 4 stars because everyone else will give it 3!!!
Also worth noting here (and not mentioned in the Editorial Review) is that the surviving film prints for Episodes One and Two have been restored, and given the appearance of the videotape the serial was originally broadcast from. (Episode Three was broadcast from a film print, and has been left unaltered.) It's difficult to explain the difference, but you'll know it when you see it; it adds a nice sense of the experience of watching the serial when it was first aired.