One possible interpretation of the phrase "кряк для Call of Duty" is that it's a playful way of expressing enthusiasm or excitement for the game. Perhaps a gamer, while playing Call of Duty, lets out a loud "quack" (or "кряк" in Russian) when they achieve a particularly impressive feat, like getting a lot of kills in a row or completing a difficult level.
"Why do we need a stream when we can just play on max settings?" кряк для call of duty