Here is a list of all costumes and how to unlock them.
Going Under All Costumes
Default – unlocked by simply existing in the same space and time as Going Under
The Contractor – unlocked by finishing Joblin
The Flirt – unlocked by finishing Winkydink
The Miner – unlocked by finishing Styxcoin
The Zoomer – unlocked by finishing overtime 1
The Fool – unlocked by finishing overtime 2
The Soldier – unlocked by finishing overtime 3
The Haunt – unlocked by finishing overtime 4
The Uncanny – unlocked by finishing overtime 5
The Crustacean – unlocked by finishing overtime 6
The Impostor – unlocked by finishing overtime 7
The Contractor – unlocked by finishing JoblinThe Flirt – unlocked by finishing WinkydinkThe Miner – unlocked by finishing StyxcoinThe Zoomer – unlocked by finishing overtime 1The Fool – unlocked by finishing overtime 2The Soldier – unlocked by finishing overtime 3The Haunt – unlocked by finishing overtime 4
The Crustacean – unlocked by finishing overtime 6The Impostor – unlocked by finishing overtime 7Thanks to VahidSlayerOfAll for his great guide, all credit to his effort. you can also read the original guide from Steam Community. enjoy the game.
