There is no denying that the original Doom sparked a revolution in gaming by helping to popularise the FPS genre to the point where it is still one of the most dominant in gaming to this day. With the second game everything got bigger and harder, culminating in the battle against a huge demon monster that usually required a few rockets to the face before you could finish the game. That is unless you enabled the idclip cheat to pass directly through the bosses head. Here you would be encountered by the severed and skewered head of the famous John Romero, whose voice is used as that of the demon you were fighting. Of course, most players chose to shoot the head, which caused it to scream in pain with each shot. A few bullets later and the player has beaten Doom 2 while wondering just what id Software were thinking with this little Easter Egg.