The good news is, there's only one thing about this episode that doesn't work. The bad news is, it's the star of the series and his character, who is taking center stage more and more as the series progresses and is placed front and center here in a fashion the show has never really done before.
There actually is a whole lot to like in this episode. The two pairs of characters (Ian and the Doctor, Barbara and Susan) are in situations that are very different, but that nonetheless allow Nation to deliver some relatively painless exposition as to how the Daleks conquered Earth. It's actually a plausible and fairly vivid scenario--certainly others have commented on Nation's obsession with plagues, in this series and others, but here he paints a bleak picture of a world bombarded by meteorites and laid low by pestilence before the Daleks even made their first move. Not that humanity has given up, of course. Dortmun...
I'm actually going to give Nation a lot of credit for Dortumn. A whole lot. Because he's quite deliberately contrasting the iconography of Dortmun with the actual character, to brilliant effect. Dortmun's character calls to mind a whole host of tropes that were at that time deeply ingrained in living memory, and which still resonate today. The Rifftrax version of the Aaru movie called him "Churchill mixed with FDR", and that's exactly what he's intended to be...a stirring speaker, with an indomitable never-say-die spirit who rallies humanity into battle when our every instinct is to flee, hide or surrender.
But of course, he's completely and totally in the wrong here. Fleeing and hiding are actually pretty good ideas right now, and the hope he brings the resistance is entirely a false hope. And Tyler knows it, too--Bernard Kay plays him with the perfect amount of fatalism, going along with a plan he knows is doomed to get people killed because he understands that Dortmun's plan has such incredible amounts of narrative inexorability that he couldn't stop it if he wanted to. The bomb hasn't been tested, the plan relies on a transparent ruse, they have to commit most of their men to it, and there's no exit strategy--how could it go wrong? (And somewhere, the spirit of Terry Pratchett asks, "What if it isn't exactly a million-to-one chance?")
So there's a bunch of great stuff going on. Really, apart from the Doctor, it's all wonderful. (Okay. The Doctor and the fact that Richard Martin still hasn't learned that cardboard standees of Daleks look like exactly one thing--cardboard standees of Daleks. Seriously, just about everyone watching the Hartnell era complains about what a terrible job he did, and I was prepared to defend him at least a little until the night scene where the Dalek searchlights went not once but twice directly over to where the cardboard Daleks were propped up against a wall. DUDE!)
But complaining about the cardboard Daleks only delays me from talking about the Big Problem of this episode--the Doctor. Since the last time Nation wrote a Dalek story, the Doctor has gone from being a mischievous trickster whose antics got the rest of the crew into trouble to being the Hero of the Show. And while Nation wrote the mischievous Doctor with energy, verve, and moral complexity, he knows that a Hero has to be a flawless figure filled with righteousness and noble spirit and always ready with a witty quip and a brilliant plan.
Which translates in Nation-script to, "I think we'd better pit our wits against them and defeat them!"
The Doctor is awful in this episode. Hartnell tries to do something with the pompous, puffed, smug, arrogant "hero-speak" he's saddled with, but his default mode is to use comic pomposity to undercut his prickliness, and there's nothing funny going on here, which just leaves pomposity layered on pomposity. Every line is a thudding failure, as the Doctor belittles his allies, lectures his enemies, and gibbers out vaguely science-y sounding things as he solves the Dalek puzzle box without even noticing that there's a Dalek about three feet away listening to everything they say and do. Every single scene he's in is painful at best and incoherent at worst, and if Hartnell can't rescue a line, you know it's bad. It's probably a good thing he's going to be out of action for a while, if this is how Nation writes him.
Because the bits without the Doctor in them? Actually pretty good.