The premise is no more idiotic than many used in the second season. It's a very different Space: 1999 from the first season. They act differently, the characters behave different - those that weren't inexplicably thrown overboard - and interact in a childish way. There's a monster of the week episode more often than not and the poor thing is usually someone dressed up in a rubber suit that has you in laughter easier than it scares you. What little attempts were made to use rational, scientific explanations for unusual events are completely thrown away.
All That Glisters is a serious offender in every aspect. Its guest star plays an Irish geologist (never featured before or after but not because he is killed more's the pity) who thinks he is and acts as a womanizing cowboy from Texas. Virtually the entire episode is set inside one Eagle and one Cave (on a planet supposedly rich a mineral the Alphans desperately need to survive, a thing they never happened to mention before - or after).
The monster of the week is a living Rock (rock based living organism, I suppose) who decoyed them to the planet by misleading their central computer into "believing" the much needed mineral was abundant there. It isn't, of course. And do you begin to see the plot holes?
Then the rock kills Tony. Only he isn't dead even though his heart has stopped as well as his breathing and so on. By telepathy (please!) the Rock controls Tony's body and makes him take a part of itself into the Eagle. You see, the rock is dying from thirst as the clouds which cover the planet's sky never rain (?).
Plotwise it only goes downhill. Everyone plays out of character, the episode is of no consequence in terms of overall story development and they have not saved Alpha from its energy crisis or whatever but return laughing and joking about it. Even the Irish-Texan geologist-cowboy.
Not even SFX to make this one esier on the eyes. The highlight there is that bits of rock change color (and look like lava lamps) and there is some rain.
Boring, pointless, a waste of scarce resources and (a few) good actors.