After some major critique regarding animal cruelty targeted to the game series, developer, and producer, the Tranquillizer Gun was added to the selection of weapons in the game.
It enables players to knock out any enemy for a generous amount of time, giving them opportunity to proceed through the level without their interference. Gamers who are against the killing of animals, (despite the "kill or be killed" headline throughout the series) can now take down enemies using the new weapon, rather than killing them.
It takes about a second to knock the enemies out, but they wake up a minute later.
- Description in the in-game PDA