Daleks in Manhattan
Roots: Evil of the Daleks. The Invasion and The Web of Fear (Doctor Who villains in sewers). Phantom of the Opera, The Talons of Weng Chiang (genetic experiments involving pigs). Having the Daleks in the Empire State Building is clearly inspired by The Chase. Tallulah is almost certainly named after Tallulah Bankhead. Diagoras is almost certainly a reference to Diagoras of Melos, who was the first doubting philosopher. The final experiment is clearly intended to sound like The Final Solution. The Doctor quotes The New Colossus and mentions New York, New York (So Good They Named It Twice).
Goofs: The Statue of Liberty has a gold flame in the torch. However, the flame was only made gold in 1986 for its 100th anniversary.
In reality, the Empire State Building is a lot further away from Central Park than it looks onscreen. It is also a lot further away from the Statue of Liberty than is shown. And, just in case you think that the Whoniverse Empire State Building is in a different place to the real world one, the two shots show mutually exclusive locations.
The Doctor says that Hoover was elected about a year ago. However, the previous US Presidential election took place in November 1928 - which was almost two years before the episode takes place.
The Hooverville in Central Park didn't actually exist until 1931.
The Sewers don't look very much like sewers. For a start, there's no sewage. Then there are lots and lots of gratings, which would release a sewage smell into the street. [These two suggest that these are actually storm drains rather than sewers.] And the sunlight passing through a 2ft wide grille casts a 6ft-wide shadow on the floor, when the parallel rays from the sun should cast a shadow the same size as the grille above. Also, at that time of year the sunlight wouldn't be coming in vertically. In addition, there are far too many junctions and 90 degree bends. Even if they are storm drains instead of sewers, they don't fit. Furthermore, why is there a manhole into them inside the theatre?
Why does the Doctor use his sonic screwdriver on the manhole cover? It's not as if they are usually locked into place. [He's trying to get rid of dirt that might be clogging up the lid. Though as Lazlo's been using this particular manhole every day for a couple of weeks, there probably isn't much dirt left.]
Why do the Daleks change the appearance of their new slaves? Surely there are easier ways of making captured humans obey them (e.g. the Roboman technology seen in The Dalek Invasion of Earth).
The Daleks say that their casing is made of Dalekanium. However, that was a word made up by humans in The Dalek Invasion of Earth. The correct word is bonded polycarbide (as the Doctor notes in Remembrance of the Daleks.
How does Diagoras fit inside Dalek Sec's casing?
Why don't the Daleks recognise the Doctor when he turns up amongst their prisoners? You'd expect these particular Daleks to have seen him during Doomsday.
Technobabble: Chromatin Solution
Continuity: The Daleks' home planet was destroyed in a war, yet versions of New York exist throughout history. The Daleks have been creating bipedal pigs as slaves. They first made contact with Diagoras telepathically. The Dalek Imperative states that Daleks are supreme and other species are weak. Dalek Sec is larger, with longer tentacles than the Dalek we saw in Dalek. The genetically engineered Jellyfish-like thing has Fundamental DNA type 467-989. 989 means that the planet of origin is Skaro. They can use their sink-plunger arm to perform an intelligence test on humans.
The Doctor can use capacitors from a wireless (possibly modified by the sonic screwdriver) to create a crude DNA scan.
The pig slaves are created by the Daleks from the less intelligent humans they capture. They use the more intelligent ones as part of their experiments. The process of creating a pig-slave includes changes to the mind to make them blindly obedient. Judging by the different appearances of Lazlo and the other pigs, the mental conditioning takes place halfway through the physical changes.
Links: Martha mentions being on stage with Shakespeare (The Shakespeare Code). The Daleks refer to the material their casing is made out of as Dalekanium (The Dalek Invasion of Earth). The Dalek comment that versions of New York exist throughout history is a reference to New New York (New Earth and Gridlock).
Extras: This story has an episode of Doctor Who Confidential. The BBC website had an online commentary, which is no longer up.. It also has a behind the scenes video podcast.
Location: New York, Saturday 1 November 1930.
The Bottom Line: 'New York, New York' Daleks in Manhattan is essentially just setting the scene. As such, it's difficult to properly evaluate it in isolation. The pace and plot feel much more in keeping with 60s Dalek stories than they do with the New Series. The supporting characters are well-drawn, and there is a lot of potential for the next episode. However, the Dalek-human hybrid looks far too cute and silly to be believable.