As you'd expect from a sequel to The Lodger, which basically just dropped the Doctor into a sitcom for modestly enjoyable results, there's not much to Closing Time. The plot is minimal, the villains barely there, the danger brief. It rests itself entirely on the comedic timing and chemistry of Matt Smith and James Cordon.
Fortunately, those two elements work like a charm. Smith and Cordon are a fantastic comic duo. Gareth Robert's script gives them plenty of good material (particularly the Doctor's conversations with "Stormageddon") and they play it to the hilt. And unlike The Lodger, it's focused enough on what little plot it has that it doesn't run out of steam halfway through. It may be simple fluff, but it's a delightful little sidetrack, and enough fun and contrast to the rest of the stories that it just manages to stay out of the "filler" status of Black Spot and Night Terrors.
But he gives them so little effectiveness, and allows them to be defeated in such a goofy fashion that if you're watching it for the Cybers, you'll find to your horror it falls in the dreaded third tier Cyber stories. There are three types of Cyber-stories: the classics, which elevate the Cybermen to fascinating, mythic villains, eerie, grotesque mirrors of the dark side of humanity. The Tenth Planet and Rise of the Cybermen are really the only stories that pull this off. The second tier Cyber stories are the stories that keep them effectively threatening, but don't necessarily do anything interesting with them. These can range from brilliant (Doomsday) to mediocre (Wheel In Space), but they all use the Cybermen simply as the villain by default.
The third tier stories are those rare episodes - Revenge of the Cybermen, Silver Nemesis, and this - that can't even manage to make them effective villains. Closing Time uses them to garnish a barely-there story, then makes utter rubbish of them in the climax.
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