Because those who have played Hotline Miami will know how spot on it is, and those who haven’t will go “This is seriously based on a video game?” Before immediately getting a copy of their own.
Being familiar with the source material, which involves running around and murdering people while wearing animal heads (and which I’ve mentioned a few times already) is not a perquisite for watching the following, though it certainly helps.
Otherwise, it’s just about some guy in a wolf masks, killing a bunch of kids. Not like that’s the most common thing you’ll see, mind you…
Actually, those who have played the game will cry foul over one significant detail: the enemies NEVER miss.