I wrote this for TV Tropes’ analysis page for The Nightmare Before Christmas. The content may also be found there, where it is freely editable: this was not a particularly in-depth look and if you have any thoughts you’re welcome to add them. (Just remember it’s meant to be written with one authorial voice.) Areas to expand on include possibly camera angles, some more details on lighting, etc. It’s been a while since I watched Nightmare in full.
The Nightmare Before Christmas is a very dark film, and not in the sense that a bunch of ghoulies are wandering around. If you were going to trot around Halloween Town, you’d probably want a torch: heavy shadows loom over in this town of monsters. But lighting isn’t the only thing used to create the slightly off feel of Halloween Town, with the film taking a lot of tips from old German Expressionism in areas such as set design.
It is worth noting, outside of the town, Christmas Town is as cheerful as you’d expect and the real world is far more plain. These are very much elements used to give the town its own separate flavour. These elements are also used commonly in Tim Burton works, and while it would be unfair to put too much undue emphasis on Burton despite the title*, it is very much designed in the style of Burton’s previous movies. See also Burton’s depiction of Gotham City in the 1989 Batman film.
Take the shot to the top right, a part of the movie on a few of the covers and posters. The set is not particularly realistic, with the cliff that curls into itself (and later, begins to unfurl as Jack walks down it). Like Expressionism, the focus is on setting a mood with no real attempt at realism. For instance, take this image and this image from The Cabinet of Dr. Caligari, a particularly famous Expressionist work which used painted backdrops to enhance its visuals. Nightmare likewise tends to go for a “pop-up book” style to its backdrops, giving an immediate feel of unreality. The rest of Halloween Town doesn’t fare much better, with jagged sharp designs, as can be seen here and especially here.
German Expressionist acting was also quite stylised, as were most German silent films at the time. Caligari again had its actors perform deliberately “dance”-like motions, and while Nightmare is not a live-action its character designs do follow up as something of a natural extension, especially given the sets. Jack Skellington, with his incredible skinniness and long, long appendages, necessarily exaggerates every movement he makes. Each character is also, likewise, made more for mood than realistic movement. Partly this is why it’s hard to imagine Nightmare as anything but a stop-motion film, since the slight uncanniness becomes a vital part of its tone.
As mentioned, the lighting of the film is very dark. In the image, the tombstones can be seen giving off extremely large shadows, and this can be seen a lot throughout the film. Similarly, Oogie Boogie himself is shown through dark shadows of himself before actually making an appearance, during “Kidnap the Sandy Claws”. One particularly famous example of this sort of thing is Nosferatu‘s silhouette creeping up the shadows of stairs. Nosferatu itself is a good example of how Expressionism segued into horror (as well as, unrelatedly, Film Noir). And, of course, while Nightmare itself isn’t really a horror, its influences can similarly be seen through the film — practically a given considering the premise. Another example of this villainous silhouette is this picture from M, though the figure in that film is eventually revealed to be something other than a stereotypical “villain”.
*Tim Burton’s The Nightmare Before Christmas was directed by Henry Selick, with Burton taking a fairly indirect role despite initially conceiving the idea.