THE HOUSE OF THE DEAD: Remake

As the description says, you need to kill all scientists in a single chapter of the game. They need to actually die from you shooting them, not from enemies killing them, so bear that in mind. Also, like with Saviour (50G), it doesn't have to be every scientist on every route, just every scientist you encounter on whatever route you take in the game.

This is easy enough to do, and you can even use the same trick as in Saviour (50G) to reload a chapter to try again, but that's not really necessary here since it's easily done in the first chapter of the game. Using the grenade launcher is a great way to practically guarantee you kill every scientist, since the explosion tends to wipe out anything on screen.