All you have to do is start the game and when the Title Screen appears, where you have to press enter, you simply put in the "Konami Code":
Up Arrow, Up Arrow, Down Arrow, Down Arrow, Left Arrow , Right Arrow, Left Arrow, Right Arrow, B, A, B, A, Enter
Credit for this Solution goes to Steam User Cronkllr, who shared the solution here:
https://steamcommunity.com/app/253610/discussions/0/62070096...