Press the green flag TWICE (or even three times). Cuphead is challenged by a no-good pirate to a fight! Keep shooting him till you win. If it gets to hard, get a friend and choose "two player" mode. Be prepared for scurvy sea creatures along the way! Cuphead: Move - WASD Shoot - space Parry - V Mega Blast - C Mugman: Move - arrow keys shoot - P Parry - O Dash - I DISCLAIMER: you cannot parry while shooting.
Thanks to DogToon64 for the sprites at Spriter's Resource. Original game by MDHR studios. V1.1: actually winable, death screen improved a bit, knockout screen improved a bit. V1.2: grainy filter added, iris transition effect added.