After perfunctorily dispatching last episode's cliffhanger, "Crisis" finally gets the hang of the advantages this premise provides that no other does. The Doctor and his companions figure out a way to take the phone off the hook using corks to prop it up, and they make inventive use of a spray can, a gas tap and a match to create an improvised bomb to attract the attention of the police. You could perhaps quibble about the ease of lifting the "oversized" objects, but the general idea of the script comes into focus tightly here. The tiny heroes use improvised tools to overcome the limitations of their size in order to foil the villain's plot.
Or they would, if not for the fact that the villain's plot is primarily foiled by a switchboard operator and his own astonishingly mistaken belief that he can masquerade as an entirely different person with a higher-pitched voice, a different regional accent and a mild lisp simply by putting a piece of cloth over the mouthpiece of the telephone. He doesn't even attempt to disguise his voice--it's as though he assumes hand towels have magical powers. Certainly the Doctor's plan helps by forcing him to talk to the operator a second time, but it's frustrating to realize that there's no need for either scene. The call to the Ministry is an unnecessary contrivance, and Forester has to be bright enough to realize that "he's already left for his boating trip" is a better plan than "oh, but I'm certainly Farrow. Can't you tell by my slightly muffled voice that sounds otherwise exactly like the person who was just on the phone?" (Then again, it's the same episode where Smithers suddenly says, "Hey, maybe I should have tested this new insecticide to see if it kills bees and earthworms!" Maybe he leeched the intelligence away from Forester and turned him into a less competent villain.)
If they'd left off those two scenes, then the Doctor's bomb plan would have been more consequential to the plot and added more drama. Then again, given that this episode was mostly cobbled together in the editing room out of two other episodes, it's probably amazing that it came out as well as it did. As it is, the only slightly ropey cut is when they jump mid-conversation to Barbara insisting they stay and raise the alarm regarding DN6, and that's only ropey because it stands out as markedly different from the editing in the rest of the episode. It's actually a fairly modern and pacy cut, the sort of thing you'd probably do these days without sweating it too much. Verity had it right here.
And at the end, the mysteriously-repaired scanner (I know, they probably didn't think audiences would remember over what was originally intended to be a month of real time) displays the title of the next episode. Handy, that--if it had happened after they stopped using individual episode titles, the Doctor could have learned about the Daleks' appearances virtually every single time.