Agent X is a mobile exclusive entry in the Mystery Case Files series of hidden object puzzle games. The player takes the role of a member of S.A.N.D. (Secret Alliance of Nebulous Directives), a secret organization that investigates bizarre occurrences around the world. The game was released in an episodic format with new episodes being released weekly. Each episode contains a number of scenes from a certain occurrence. In addition to the episodic story mode there were also daily puzzles each consisting of a random scene that was automatically chosen every day.
The gameplay works like in other hidden object games with the player's crime computer generating a list of objects that the player then has to locate within the current scene. When the player finds an object he moves a cursor to it and clicks on it and it's removed from the scene. Once all objects have been removed the crime computer will analyse the clues and explain what has happened. Scenes are often larger than the screen size and therefore it's necessary to scroll through the scene by moving the cursor to the edge. If stuck, the player can use a hint to get some help in locating an object.