Here is the full list of all 28 Arcade Spirits: The New Challengers achievements.
Complete all romances.
Romance Grace.
Enter the finale while Gutsy.
Romance nobody.
Enter the finale while Quirky.
Lose all three major FoD2 matches.
Romance Grace and Jynx.
Romance Jynx.
Romance Rhapsody.
Romance Domino.
Encourage Iris to be Orderly.
Mixed wins and losses in major FoD2 matches.
Enter the finale while Steady.
Romance Zapper.
Romance Locksley.
Perform the Ultimate expression of pizza on a bagel.
Romance the Rival.
Encourage Iris to be Chaotic.
Clear Level 8.
Enter the finale while Kindly.
Clear Level 7.
Clear Level 6.
Win all three major FoD2 matches.
Clear Level 5.
Clear Level 4.
Clear Level 3.
Clear Level 2.
Clear Level 1.