Some kind of stealth shooter where you and the bad guys have very realistic anatomy and no healthbar. You can't be killed by being shot in the foot but you're disabled. Shoot someone's finger off and they might not be able to use a rifle, help in pain, leave a blood trail to follow. Chest shots generally kill you but it's the lungs it's not instant like the heart or central blood vessels. Bone shots are agonizing and totally debilitating.
Caliber and velocity are all calculated and what damage is done.
I know this is kinda grim, but lots of video games have done parts of this, especially Sniper Elite, but also RDR2, the Resident Evil REmakes, MGS:R, and more. I just want it even more detailed and collected in one game. I've been thinking about this since PS3-era and I think the tech is ready now.