Hey, it's my friend Jason's birthday! Happy birthday, fellow Who enthusiast! There are certainly worse ways to celebrate than the first two parts of The Pirate Planet.
So there have been moments here and there, but in general the majority of stories recently have been more concerned with serious threats and dangerous situations, with bits of levity thrown in. But this story, much like The Ribos Operation right before it, is much more interested in being fun first and dangerous second.
Note that's "fun", not "funny". While there are some jokes and humorous situations scattered throughout (as one might expect from author Douglas Adams -- arguably the most famous writer to work on the show), the cast generally aren't treating this like a comedy. Well, Tom Baker might be, but as his performance here in indistinguishable from surrounding stories it's hard to tell (and as we'll see in part three, he does know when to let that carefree mask drop). But Bruce Purchase, as the Captain, doesn't seem to be, even if he is chewing up the scenery -- there's the scene where he talks tenderly to his parrot that suggests the bravado is a cover, and the Doctor notes in part two that he and Romana are in great danger from the Captain. "What, from the Captain?" Romana says. "Oh, he's just a terrible old bully. All that 'by the evil nose of the sky demon' nonsense is just bluster." "The Captain is a very clever and very dangerous man. He's playing with us," the Doctor replies seriously.
But nevertheless, fun is still the order of the day for these two episodes, and as a result we're presented with an hour of highly entertaining television. The stuff about how to fly the TARDIS is nice (and gives us an in-universe explanation for Tom Baker's mouth wound) and the way Romana can get the native Zanakians (Zanakans? Zanakese? Zanish?) to chat with her while the Doctor continually fails also brings a smile to the face. Plus the Doctor's entrance onto Zanak's bridge is great stuff. And while the Captain is full of bellowing bluster, it's still entertaining bluster, with many creative phrases. Yes, there are occasional missteps ("I'll never be cruel to an electron in a particle accelerator again", the Guard Captain waving goodbye to his departing aircar), but these are more than made up for by the surrounding material.
And beneath the layer of fun is a fabulous SF concept: as we learn at the end of part two, Zanak is a hollow planet that teleports across the galaxy around other planets and exploits all the mineral wealth and energy from the captive planet. "Romana," the Doctor says urgently, "we've stumbled on one of the most heinous crimes ever committed in this galaxy." It's an impressive and fascinating idea, and it will be interesting to see what the next two episodes do with it. Well, so long as our heroes can escape the clutches of the Mentiads...