The first episode is pretty solid, but it quickly falls apart due to the cheap sets and costumes, plus whatever stereotyping was going on with the Master’s disguised magician fellow (the most pointless Master disguise which is saying something.) I feel like if they’d filmed it in a quarry then some of the sets would have fared better.
I think this was discussed in the documentary iirc, which I appreciated for going into detail as to why the story ended up as crap as it did, but didn’t necessarily treat it as such.