>>5364176Are you looking more for a Belle Epoque Alphonse Mucha art nouveau type aesthetic, or a later art deco aesthetic? You can definitely find a lot of videogame concept art referencing that - Bioshock and Bioshock Infinite (the sky city Columbia) come to mind. You could use the Cthulhu or Mafia videogames for the 1930s look.
Here is a picture of a weird trombone gun I found hehe, it reminded me a bit of the strange rifles in Disco Elysium that are sort of a hybrid between WW1 Lewis machine gun and old flintlocks (I have not played it, just watched about 25% of a youtube no commentary playthrough)
