- The buildings are all (or mostly) Art Deco style. Indeed, the art style has been described as Dark Deco.
- Men's fashion seems to be 1930s-40s-era with fedoras being quite popular, though men's fashion tends to change slowly, while women's fashion is more 1940-50s-era.
- Multiple rigid airships are seen throughout the series, though the practice of building large rigid airships (zeppelins) went out of favor after the crash of the Hindenburg. Airplanes, Batman's futuristic fighter jet excepted, are generally powered by piston engines. One episode prominently features an autogyro.
- Computers, VCR and video games are common, yet television broadcasts are in black and white.
- Not to mention things like digital phones, satelites and virtual reality.
- Gene splicing is known, and this, rather than surgery, provides the explanation for the origins of the Doctor Moreau expy's animal-men... But his laboratory (and pretty much any laboratory seen) is much more reminiscent of classic-movie Doctor Frankenstein's dungeons than a modern research facility.
- Nobody objects to women having careers or Lucius Fox, a black man, being in a prominent position at Wayne Enterprises.
- Uniforms are 1960s-era and SWAT teams exist, but weapons are 1920s-70s, with M1921 or M1928 Thompsons and 100 round drum magazines being very common while police — or at least patrol officers — carry revolvers and shotguns for the most part.
- Cars are 1930s-40s, Liebherr-type cranes exist, helicopters are from the 1980s.
- Charlie Collins' driver's license◊ was issued September 25, 1991, expires March 17, 1995 and lists his date of birth as March 17, 1946.
- A photo from Thomas Wayne's graduation, which Bruce says happened 40 years prior, is dated 1908.
- Jonah Hex's story is said to happen in 1883 and implied by dialogue to had happened only a 100 years before.
- The Gotham State University football team wears leather helmets and long-sleeved football sweaters, but plays in a domed stadium.
- In the Direct to Video, Subzero, the music Dick and Barbara listen to is almost exclusively 40's-ish jazz with some doo-wop thrown in.
- The tech, fashions and architecture seem to take quite a jump forward by The New Batman Adventures, despite it taking place only a few years after the original run.
- By the time you get to the flashbacks in Return of the Joker, integrating DNA into microchips is possible.
- In one episode you can see a black and white flat screen television with remote control.
Anachronism Stew / Batman: The Animated Series
Intentionally invoked by the creators to make when the series takes place ambiguous, largely as a nod to Batman's invention in The Thirties.