Keys are interactive objects first seen in level 8 of Perspective.
Keys are beige coloured with a brown outline. The tab has a circle-shaped hole, while the blade has two protruding round shapes. The key bobs up and down.
When the key is collected, the dog must reach the door to unlock it. Unlocked doors disappear once they are open. If more than one key exists in a level, the dog needs to collect all the keys to unlock all the doors in the level. More than one key is necessary to obtain only when the player controls two dogs simultaneously.