“Things in ‘Knock Knock’ are a little bit magic because it’s a horror film packed into a Doctor Who episode, and almost every horror film is at least a little bit magic.”
“It’s the Doctor and his companion righting wrongs in a worthwhile, thorough, and satisfying way. One can imagine the churl who’d object to any of this, but one cannot agree with him, nor quite respect him.”
“This is of course the second episode in a row concerned with technology that is both incredibly powerful and colossally dumb, causing enormous harm through a misguided and clueless desire to help.”
A small cast works well together to tell a simple monster story, reintroduce us to the TARDIS, provide a good jumping-on point for any new viewers out there, and give the longtime fans some Easter eggs right before the holiday.