Easy mask that will allow me to see only a part of the screen

So I want to make a 2D Scroller, but with the visuals resembling the Haunted House in some Mario games, where everything on the screen is pitch-black, exception making a small circular area around the player. I am kinda new to UE4, but I already tried deleting all light from the level and adding a light soucre attached too the camera/player model, but with no effect. How should I approach this?