Boob Wars: Big Breasts Versus Flat Chests, a hentai visual novel / card game hybrid, developed by Softhouse Seal. Published by MangaGamer in March 21st, 2014. Available at Nutakus digital store for $25.00. Uncensored genitals. Available for PC Windows operating systems (Win 7 is minimum).
You are Takamura Manabu, a member of a secret organization of erorists (terrorists?). Your mission is to seduce the queens of the two warring boob tribes, and bring an end to the destructive conflict.
Source: N4G PC Hentai Game Review: Boob Wars, Big Breasts Versus Flat Chests