The Captain is another in a line of wonderfully over-the-top villains in Doctor Who blessed to exist in an era when such personae were keenly encouraged. Bruce Purchase if perfect as the blustering cyborg, and Andrew Robertson is ideal as his snivelling underling, Mr. Fibuli. Whereas the Captain's intentions might be more bombastic, Mr. Fibuli's motivations are purely on his job. He bears no malice towards anyone. He's just doing the job that he's been ordered to do without really thinking of the consequences. He's the perfect middle manager.
The Captain, on the other hand, is a twisted satire on the traditional stereotype of a pirate captain. His eye patch is an electronic eye, his peg leg is a cybernetic arm, and the parrot on his shoulder is a killer robotic bird that seems to manage a quota of killing one ineffectual orderly a day. The Captain controls the bridge, there's a mast or two to lash prisoners to, and there's even a plank to dispose of prisoners. It's an example of what Doctor Who does best - taking an established legend or story and turning it completely around into something new.
Tom Baker is a tour de force in this episode, too, as it is quite evident that Douglas Adams's scripts are to his liking. It's not often that Baker balances the increasing number of comedy scenes with scenes requiring deadly seriousness, but he does it in this episode. His loud bluffing with the Captain in the engine room is nicely countered with an understated gravitas when he's explaining how desperate the situation is to Romana. In a later scene in the mines, Baker ups his game even more when explaining how Zanak works to Romana and Kimus. It's no wonder that I latched onto Baker's performance as a young boy when I first saw this, and I reckon a few thousand more kids at that age could say the same thing.