How did the revenge attack of stick figure get gatling's weapon?

The revenge blow of stick figure can make gatling's weapon pass the final level. Mr.VengeanceAct is a game created by tmifx game production team according to some settings of Marx Payne and other games. There are four episodes at present. The game is a light gun game just like War of Resistance against Japanese Aggression: A bloody battle on the beach. The characteristic of this kind of game is that the character controlled by the player can't move freely, and the movement is completely determined by the game system, so it can only aim, shoot and reload.