To me, the 1984–86 years were terrible ones for Doctor Who. However, if I was to pinpoint a better episode, this would be it.
There's an interesting (if not slightly tired) moral vs. amoral vs. immoral comparison in this serial, and the ending is OK, certainly no worse than Russell T Davies would spit out in the modern series. Kate O'Mara plays the Rani, another renegade Time Lord – although, when I come to think of it, almost every Time Lord I've ever seen in any serial could be described as a renegade. They're basically human. Her performance is actually rather good. Colin Baker is his usual self, and Peri shows some backbone for once.
If you ever see this story, I challenge you not to ask the same question at the end that I did: “What was with the dinosaurs…?”
Not too tragic as a whole, but a little slow throughout.