In the segment "High Score," Marcus tears out an opponent's heart in a finishing move, like in the popular video game. It is then followed by "Marcus Wins" titles, which happens upon performing the infamous "Fatality."
When Marcus tears out an enemy's heart, the "game world" proclaims that Marcus Wins, with a Perfect Victory and performed a KILLER INSTINCT move. A reference to the finishing moves of Mortal Kombat and Killer Instinct (among others).