The animation of Cuphead's head as a planet and Mugman flying around it in an airplane at the beginning of every episode is a homage to the old title card for Universal Studios.
Like the game, the series has an artificial grain effect to give it the effect of a 1930s cartoon.
Grim Matchstick has design origins in creatures from 'Popeye the Sailor Meets Sinbad the Sailor'.
The Inkwell Isle map at the beginning of every episode shows Cala Maria, Captain Brineybeard and Grim Matchstick, three of the bosses from the video game.
In the game, King Dice is the immoral manager of a casino. In the series, he's a sleazy game show host.