THE HOUSE OF THE DEAD: Remake

This is cumulative over your entire time with this game, any game mode, win or lose. Lots of different enemies will throw projectiles at you, and shoot them is what you need to do for this achievement. Actually, even using the grenade launcher works, as the explosion will deflect enemy projectiles too. Personally, I got this without even trying by the end of my second playthrough. Considering you'll be doing more than that, this is pretty tough to miss. If you somehow need to grind it out, just keep enemies alive that throw projectiles at you and keep shooting them down.