This is a list of pre-release and unused content for Cuphead.
Chad and Jared Moldenhauer had created around 150 different character designs, including a kappa in a top hat and characters with a plate or fork for a head, before settling on Cuphead as the main character.
Concepts of Cuphead
Before deciding on a final design for Cuphead, Studio MDHR went through a long process of character design, with numerous concept art depicting the various iterations before the final design being available to view:
Sometime in 2015, a playable demo of Cuphead was premiered at gaming conventions. It showed off several bosses and had versions of a few themes that are still in the soundtrack today. The background music was created digitally using a jazz soundfont. (unlike their final game counterparts which utilized a live recorded band)
Botanic Panic (Featured in 2015 demo):
Honeycomb Herald (Featured in 2015 demo): https://drive.google.com/file/d/1oLERObBf8wGK5Ut7FNmX75gWu8QYmrod/view
Aviary Action (Featured in 2015 demo):
Clip Joint Calamity (Featured in 2015 demo): https://drive.google.com/file/d/1-s7RKKENfq1F-0pw-mbetWvcQfQEWKCs/view
Original Inkwell world map theme (Featured in 2015 demo):
During the game's development, these tracks were originally used as place holders, In the online footage of the Cuphead demo, The same theme could be used for multiple bosses, and were often swapped around. Only later on were they incorporated into the final soundtrack.