Complete the indicated chapter to unlock the corresponding dress.

Dress	How to unlock
Classic	Infernal Train (Chapter 6). When equipped you will regain health when shrunk.
Misstitched	The Dollhouse (Chapter 5). When equipped your Shrink Sense duration is doubled.
Royal Suit	Queensland (Chapter 4). When equipped your health is limited to four roses total.
Silk Maiden	Oriental Grove (Chapter 3). When equipped your enemies drop twice as many teeth.
Siren	Deluded Depths (Chapter 2). When equipped your enemies drop twice as many roses.
Steamdress	Hatter's Domain (Chapter 1). When equipped breakables drop more teeth and roses.