Press space to shoot. Arrow Keys to move. Add in the music using the ones i provide you with such as floral fury, sugar land shimmy, botanic panic, etc. Edit the "dat boi" Sprite to make him different and remix this to make your own cuphead game/battle.
Thanks to the original battle engine by @RndmThngz31297 ! Thanks to Studio MDHR for Cuphead! Thanks to Gravity Falls/Disney XD for Bill Cipher! NOTE: As you will clearly realize if you get Bill down past 50 HP, this is an unfinished work in progress. I will finish this another time.