HoiHoi-san, full title Ichigeki Sacchu!! HoiHoi-san (一撃殺虫!!ホイホイさん One-Shot Bug Killer!! Interceptor Doll HoiHoi-san), is a manga by Kunihiko Tanaka that spawned a PlayStation 2 game.
In the year 20XX, insects have become immune to all pesticides. To combat the rising plague of cockroaches and other household pests, the tiny, doll-like extermination androids known as "Hoihoi-san" were created. They can hunt down insects and kill them with such miniaturized weapons as minuscule machine guns and tiny combat knives. They can also (and at the same time) be treated as dolls, by dressing them up in costumes and buying accessories for them. The main robot of the anime wears a maid uniform and rabbit ears as accessories.
This third-person shooter game aims at completing levels and defeating hordes of various kinds of insects, all while avoiding collateral damage to furniture and other household items. Completing a level gives the player credits with which one can buy upgrades for the Hoihoi-san, ranging from the useful like missile packs, ammunition and weapons upgrade but also less useful items like new clothing and new voices.
In the game, the muzzle blast is about the size of the robot, which combined with an impressive rate of fire makes for a definite statement in the girls-with-guns genre. A modicum of style, finesse and Japanese tradition is retained by featuring a katana in the weapons selection. The game allows the player to use both a katana and a machine gun at the same time.
If the player acquires all Hoihoi-san accessories, the backdrop turns pink on returning home.
Source: Wikipedia, "Hoihoi-san", available under the CC-BY-SA License.