Though the girls are masters at dealing out pain, they will inevitably take damage now and again. Each hit the girls take reduces both their health gauge and their costume's durability. Their outfits slowly tear off bit by bit until all durability is lost and they're left in nothing but their swimsuits! To add insult to injury, the fewer clothes they have, the more damage they take, so try to keep your "armor" on for as long as possible.