In the game "Ninja Rush", the player takes on the role of a secret agent in an endless runner where they earn 25 points for killing ninjas that spawn on platforms. Over time, the ninjas would get stronger, requiring more hits to kill. As the player's score increases, their weapons would upgrade to make killing ninjas easier and allow for more points. This scoring and upgrading system ties into the story of the player character Agent Slick going on missions to destroy ninjas and advance to harder levels by improving his arsenal.