The Curse of Peladon was a fine story full of atmosphere and wonderful direction, the Monster of Peladon is a dull, lifeless, uninteresting political story that doesn't get going until it's final episode.
Why did this story have to be six episodes long? If this was only four episodes it would feel long-winded because the plot never advances properly. The miners believe the spirit of the god Aggedor is killing them because of new alien equipment they are being forced to use to mine a mineral called trisilicate, which the people of Peladon use the fight the war against Galaxy 5. That's the plot, from start to end, it never advances or develops, it never goes anywhere, it just feels like six episodes of characters running around not really accomplishing anything. The only real change in the plot is the introduction of the Ice Warriors in Episode 3, and even then very little changes.
The characters are not only dull, but also quite irritating at points. Queen Thalira is a queen in title only as she let's herself get walked all over by basically everyone, to the point where you're screaming "for god sake stand up for yourself" at the screen every time she appears. The chancellor Ortron seems to be constantly trying to kill the Doctor for absolutely no good reason, and all of the miners are really pathetic and weak characters who never accomplish anything, and seem to be good only at getting killed.
The only good characters are Commander Azaxyr, the Ice Warrior leader who is the only character who actually makes sense and has a clear motive, and Eckersley the Engineer who goes round double-crossing everyone and makes for the hidden bad guy of the episode.
The acting is quite weak, with the exception of Donald Gee. Nina Thomas, Frank Gatliff and Rex Robinson all give very wooden performances that are hardly fun to watch. Most of them seem rather bored, even Pertwee looks tired towards the end, and Elisabeth Sladen's performance after the Doctor's death in episode 6 is not a sad one, but more one of "is this not over yet?", which is probably what the viewer is thinking too.
The Curse of Peladon was brilliant story, so I can see why Brian Hayles would want to revisit this world, but the sequel is not only lacking the excitement of the previous Peladon tale, it's lacking any kind of narrative or imagination that that story held.
I can easily class the Monster of Peladon as a Failure!