Robber is an action game where the player controls a thief that has reached the safe of a castle dungeon vault. The game contains three different screens that the player has to find a way through without getting killed. In the first room there are three objects that need to be collected: a stethoscope, a door key and a safe key (which is hidden). There is also a guard patrolling the room and it is necessary to avoid its torch beam. The second screen involve moving over a bridge whose pieces is regularly vanishing. The third and final screen contains multiple sections. First it's necessary to swim through a flooded cave full of deadly jellyfish and it has to be done with a limited air supply. Then there is the dark catacombs where only the man-eating birds are visible and finally the player has to get past gigantic bouncing balls before reaching the safe.