It's so bad it's good. I know for some it represents the absolute nadir of Who. I agree that Tom was out of control as an actor, and that Graham Williams was just too nice a man to take the action required. And yet......
Taken in isolation, this story is high camp at its' funniest. Tom and Graham Crowden in a mighty contest to out-ham each other (an honourable draw).Ludicrous monster costumes, and comedy sound effects.
It was a crazy, mixed up mess. As a one off it was hilarious, but that is with hindsight. The actual story was quite good, and with a serious treatment, would have worked well. Anthony Read must have been holding his head in his hands, when he saw the finished article.