The enemy AI was praised - it would adapt not only to the player position, but also to their skill. Some rooms contain inaccessible items - smaller "thieves" show up from a passage in the wall, try to grab the item and bring it back to another point in the room or disappear with it. The player is able to obtain the item if they shoot the thief at the correct time. Bonuses are awarded for reaching certain parts of the level under a certain limit of time or number of lives, bringing an object to a room or simply by playing poorly, where the game helps the player.