The Mystery of the Crystal Portal is a hidden object game in which the player is tasked to help the character Nicole Rankwist uncover clues in order to find her father. This game offers a different kind of gameplay from other hidden object games in that players are not given a list; instead, players have to explore each scene thoroughly to discover the scene’s Key Objects. These interactive items can be found by hovering over objects until the cursor changes into the shape of a hand.
When clicked, the Key Object will be surrounded by circles; these circles contain images of the items that the players need to find in the scene. Once located, these items have to be dropped onto the Key Object. This removes the items from the scene. The items may be found in plain sight or hidden inside containers. More than one key object may be present in a scene; there are instances when the player must find a new key object in order to finish the first one. A bar at the bottom of the interface indicates how many Key Objects are present in a scene. When all of the items in a Key Object have been found, the Key Object will disappear and may reveal other items behind it.
The game has no time limit. It provides players with hints that recharge after 90 seconds.