To acquire the Clothes Horse achievement you must change into all clothes (and costumes) available in the mall. Some of the outfits are available in multiple stores, so you might not have to visit every store to get the achievement.
Paradise Plaza
Shoekins
Kids Choice Clothing
Universe Of Optics
SporTrance
Ye Old Toybox
Tyke N' Tots
- Green Ratman shirt and denim shorts.
Colby's Movieland
Mega Man Helmet available in the Toy Store inside.
Child's Play
Wonderland Plaza
Fanfare Fashion
Shoes Of A Lifetime
Casual Gals
Small Fry Duds
Homerunners
Scuffs and Scrapes
Fine-Lady Cosmetics
The Lens Zen
Modern Businessman
Lovely Fashion House
Kokonutz Sports Town
Run Like The Wind
Al Fresca Plaza
Brand New U
Eyes Like Us
Entrance Plaza
Men's Storehouse
Rafael's Shoes
Nichol's Ladies Apparel
J.W.'s Sporting Goods
Refined Class
Sports High
Groimin
Space
Fashion Fiesta
Distinguished Gentleman
Gramma's Kids
Children's Castle
Fine Lady Cosmetics
Modern Businessman
Star Sporting Goods
Women's Lib
Wallington's
Jamming Juvenile
Ladies' Space
The Shoehorn
In The Closet
Outta Sight
Kathy's Boutique