Heart Work

Heart Work is a 1997 visual novel by Active.

Yuu Asakura is just a common high-school student. One day, he accidentally changes his school bag with one belonging to a hitman. Once he discovers that by opening the bag in his family's apartment, he also finds the man's gun. The weapon for some reason feels attractive to the boy, and he ends up firing it, thankfully without wounding anybody. Scared but still weirdly attached to the gun, and mildly afraid of the original owner, Yuu...Well, this is a visual novel, so it's up to the player, and by that we mean, Yuu, to decide what Asakura must do with the gun and the other items in the bag.

It was translated to English by Kitty Media in 2009. The artist behind the character designs is Sei Shoujo, the same behind Bible Black and STARLESS. And the storyline is as dark as of these works.

Tropes used in Heart Work include:

All Girls Want Bad Boys: When Nakamoto sees Yuu initiating a robbery right in front of her in one of the game's routes, she don't gets scared or anything, but comments she never expected him to be so "manly".
Absurdly Youthful Father: Ending 3. If Morikawa is indeed pregnant by Yuu after he was forced to rape her, he is this as a high-schooler student..
And the Adventure Continues...: Ending 5 and 6. Yuu gets a new tape with a new assassination mission, the difference is that thanks to a Heel Realization in the route to 5, he never tries to get away from the gun and seems very willing to keep being an hitman.
Asshole Victim: Angel defines Kengo as such while explaining her mission to Yuu(he is an arms dealer knowingly making deals with criminals), and what really makes the mission morally ambiguous is that Angel is also willing to assassinate his innocent daughter.
Babies Ever After: Ending 3. In Morikawa's letter, she implies she is pregnant by Yuu after he was forced to rape her by Ishihara.
Bare Your Midriff: Morikawa wears only a crop top above her waist, leaving her midriff exposed.
Bolivian Army Ending: Ending 1. We only hear gunshots as Yuu goes into confrontation with the police.
Cleavage Window: Morikawa wears a crop top with a square-shaped window for her breasts.
Dangerously-Short Skirt: Morikawa is implied to be this kind of girl, but there's not a lot of scenes which show it. She does kill Yuu in a gun duel if the player makes the wrong choices though.
Face Heel Turn: Yuu may go through this in several ways through the game's routes. It may involve using the gun in the school, raping Nami after her father is killed, or snapping after Ishihara frames him before Yuu warns the police.
Four Eyes, Zero Soul: Masaki Ishihara, who is seen constantly wearing glasses, is an hitman seemingly warped by the powers of the gun, and by what we see in game he likes to rape his female victims directly or indirectly. By what Morikawa explains, however, he was normal before finding the gun, what gives him shades of Tragic Villain.
Groin Attack: Ending 14. Yuu kicks Ishihara in the groin before shooting him.
Heel Realization: Ending 5. After Angel kills Nami's father and breaks the girl's mind, Yuu has an epiphany and decides to truly become an amoral criminal after having helped Angel in doing that.
Hero Antagonist: Morikawa becomes one to Yuu if he snaps in the school and Misaki don't kills him. Whether she succeeds or not in stopping Yuu depends on the player's choices.
Hope Spot: Ending 17. Ishihara seemingly spares Yuu and his stepsister after seeing Yuu's moral decay as he had sex with his sister...then he shoots Yuu from the hallway, fatally injuring him. As we only see events of Yuu's point of view, we don't know what happens to Misami, but it is pretty much said he was going to kill her soon after.
Hot Mom: Misako, Yuu and Misami's mother, it's pretty good looking and curvaceous.
Hot Teacher: Mizutani is a teacher in Yuu's class and is also beautiful and curvaceous. However, despite her hotness, she is more feared than loved thanks to her strict attitude.
Living Weapon: The gun Yuu accidentally obtained from the hitman seems to be capable of changing the mind of its wielder into one of a psychotic violent killer, presumably so it can kept being used and obviously not destroyed. And its effects don't seem to wear off if the wielder loses contact with her, though depending on the player's choices Yuu may break out of its influence.
Moral Event Horizon: In-universe, Ending 5. After the assassination of Nami's father and Angel drugging the girl to the point of reducing her to a baby mentally, Yuu thinks there's no moral lines for him to cross after helping on that. When Angel cryptically suggests for him to rape Nami as a form of "kindness", he does it.
Ms. Fanservice: It is a hentai VN but most female characters dress modestly. Morikawa's outfit however is filled from the bottom to the top with fanservice tropes.
Multiple Endings: There's 19 of them, though some are basically "mission failed" versions of others.
Mutual Kill: Ending 3. Angel and Ishihara end up killing each other after Yuu alerts the police where Ishihara was supposed to meet her, and she mistakenly thinks he trapped her.
Pet the Dog: If Yuu decides to be the backup of Angel in the assassination mission, she spares Nami and affirms she did it because Yuu asked, someone she barely knew. However, she injects a drug to break her mind so she can't remember how her father was killed or who did it. Yuu affirms in his narration that he don't considers it any different of death at all.
Pragmatic Villainy: In Ending 5, Angel spares Nami, but can't simply let her go and drugs her so she can't be interrogated by the police.
Rape by Proxy:
- If Yuu decides to not take the gun to the police and also not to school, when he comes back Ishihara will appear in his apartment and forces him to rape someone, who changes depending on the player's choices.
- In Ending 2 and 3, Ishihara forces Yuu to rape Morikawa.
- If Yuu snaps inside the school, he tells the other boys to have sex with the girls.
Rescue Romance: Ending 4. Nami is shown to be attracted to Yuu after he saves her from Angel. The game lefts ambiguous if it's a Star Crossed Lover situation or not, since she don't recognizes him one week later.
Stupidity Is the Only Option: Averted. Delivering the gun to the police like a normal person would is a choice. However, doing it before or after seeing completely the VHS tape and answering or not a call from the hitman results in three different endings.
The Nineties: Made and set in this decade, and it shows. There is a VHS tape in the hitman's bag.
Vapor Wear: Morikawa doesn't wear a bra and the fact her nipples are showing through her crop top proves it.
Victorious Childhood Friend: Ending 14. After her confession and the two managing to survive an encounter with the owner of the gun, Misaki and Yuu start a relationship.
Younger Sibling Fetishization: Averted, mostly because Yuu's little sister is a pretty minor character. In Ending 17, however, Yuu does have sex with her, and enjoys her suffering as he rapes her under Ishihara's orders.
Zettai Ryouiki: Morikawa's translucent brown stocking goes up her thigh. Class A.