Beat the Devil, and a strange door appears on Cuphead's world map. On the other side is a tournament of five Deltarune bosses, fought in Cuphead's run-and-gun style:
Jevil (Chaos Contract): card-suit rings, teleport ambushes, a devilsknife rolling along the floor.
The Roaring Knight (Knight Contract): sword volleys, falling triangles with one safe gap, a screen-wide slash.
Tenna (Broadcast Contract): thrown stars, lightning on your spot, card waves.
Flowery (Final Contract): petal fans, pellets that turn on you, axe-kick shockwaves.
Single player. Simple, Regular or Expert on Cuphead's own difficulty card.
Pink bullets can be parried. Cuphead's own death card, scoring and KNOCKOUT.
Each boss fights to their own Deltarune music, and Flowery to Flower Man.
No rewards: just the next contract and bragging rights. Once all five are signed, rematches start again from Jevil.
Your Cuphead save stays as it was. Tournament progress is kept separately.
You need Cuphead and Deltarune (chapters 1–5) installed. The bosses' sprites and music are read from your own copy of Deltarune when you play. No game files are included.