Growing Pains: The Heart's Measure

A breast expansion romance visual novel where the changes are real. Hana, a shy and introverted art student who has always been self-conscious about her petite frame, discovers that her emotions have a strange and literal physical manifestation—whenever she experiences strong romantic attraction or emotional vulnerability, her breasts begin to grow uncontrollably. As her feelings for her charming new classmate, Ren, deepen, so do the changes in her body, forcing her to navigate the complexities of dating, self-acceptance, and intimacy while hiding her secret.

[From itch.io]