Lost in Shadow is played largely in the background of the game environment as the player controls a boy's shadow, which must climb the shadows of a tall tower, rife with puzzles and enemies. He is accompanied by a sylph that can alter the direction of the foreground light sources, altering the alignment of shadows upon which he climbs. There are times in the game when the boy is able to materialize into the 3D world and briefly interact with the objects themselves as opposed to simply their shadows.