Dieselpunk

Dieselpunk is like a Steampunk, but instead of Industrial revolution we got both World Wars and period between them.

Aesthetics

If steampunk is all about brass, steam, blimps and clockwork robots, then dieselpunk is steel, internal combustion, tanks and dreadnoughts (of the naval kind, and the walking boxes kind).

Whereas Steampunk borrows the fashions and aesthetics of the Victorians, Dieselpunk's primary aesthetic is Art Deco. Anything not related to machines will be very ritzy and flashy, jazz will be the dominant form of music and futurism will be the dominant form of architecture. Expect a lot of pressed and stamped metal. Thin, gilded veneers concealing oily machines (both literally and allegorically).

The overall technology level hovers around 1935: we got machine guns, cars, piston planes (and jets, but they're bleeding-edge tech that isn't found outside the military or corporations), radios and black-and-white TV sets. Electronics are something of a gray area: they exist, but they can't be very advanced. You can expect radio, radars, alarms, simple encrypting/decrypting machines and so on, but no portable phones, detectors, transistors and computers (barring occasional ENIAC-styled vacuum tube monstrosities that take up at least an entire room). In a nutshell, if it looks like your grand-granddad would like it, that's steampunk, if it looks like it belongs to your grandpa, that's dieselpunk, and if it looks like your dad used it, that's early atompunk, assuming you're 35 circa 2015 (which you are, unless you're a newfag).

Also worth mentioning that there is significant difference in mood: steampunk stories often lean on the romantical side of things, adventuring with the science of the future and all that. Dieselpunk on the other hand gets grimdarker with industrialised warfare, totalitarianism and nihilism. Even without the shadow of "The Great War/s" looming over the setting, you have the social unrest of the Roaring 20's, the Great Depression, Gangland, and ruined continental Europe rebuilding in the background to temper your optimism. Steampunk is "The Time Machine" and "20,000 Leagues Under The Sea", Dieselpunk is "All Quiet On The Western Front" and "Catch-22".

Examples

• Imperial technology (and, by extension, Chaos and Ork tech, since they like to loot their tech) is the embodiment of this. Rule of thumb: if it doesn't look like it came out of Renaissance Fair or cheap 80'ies sci-fi show (or both), it's probably a Dieselpunk design. The Imperial Guard is literally runs on it, special mention goes to Kriegers, Armageddoners, Mordians, Valhallans and entirety of Commissariat.
• Generally, every Russian or Russian-equivalent faction in sufficiently advanced setting is this; see Khador, Red Bloc; good vidya examples are Soviets from Red Alert and China from C&C:Generals.
  • Nazis and similiary themed factions tend to share this property whenever they're not too busy playing with occultism, eugenics and Tesla weapons. Kinda understandable: would you look at these penis compensators.
• In /v/, examples are Fallout (albeit if you're inclined to split hairs, that's Atompunk (50'es to 70'es)), first two Bioshocks (Infinite is more steampunky), Dishonored and Wolfenstein (from "Return to" and onwards).
• For weeaboos goes non-magical bits of Fullmetal Alchemist, half of what Miyazaki did, Avatar's Fire Nation and whole Legend of Korra.