The clues may be explicit, describing exactly how to reach the goal, or implicit, describing facts and events in the game world which need to be interpreted by the player. Of course, this categorization is not clear-cut, as the vagueness of the clues can vary between these two poles.
Example: Arrows and signs in The Legend of Zelda series are direct clues, which can guide the player through the game.
Example: Many racing games contain warnings for the next turns as signs on the side of the road.
Clues may take the form of advice, encouragement, or warning. Advice tells players what to do before they have started performing a set of actions; encouragement provides feedback that a given action is correct although the goal or the closure is not completed yet; and warning gives players advice on what not to do. Encouragement is typically used to indicate completion of low-level subgoals or to promote further Exploration of a given area or object. A more specific encouragement is to use a Near Miss Indicator to indicate that the player started performing the right actions but failed to do them correctly.
A Clue can either be an object in the game, which has to be taken or manipulated to change the game state, or plain information. In the latter case, the Clue is an Outstanding Feature and can also be Extra-Game Information if it is about something outside the Game World. Of course, the Clue may be about how to use the game controls or the game mechanics, which automatically makes it Extra-Game Information. These forms of Clues, however, may break the Consistent Reality Logic and Emotional Immersion in the game, with one example being arrows that show the way to the exit of a Level. If the clues are set within the Consistent Reality Logic of the game or support the Alternative Reality of the game, they can also be used to support the Narrative Structure.
Two typical forms of Clues are Helpers and Traces. Helpers can provide Indirect Information to the players on how to reach the goals, and Traces allow the players to indirectly deduce how to locate Deadly Traps and Enemies, for example. Other Clues provide more Direct Information, for example, arrow signs to indicate directions where the player should go or explicit warning signs about dangers ahead.
Clues, especially warnings and Helpers, may be used to indirectly guide players who have gone astray toward the goals and the main areas of the Game World thus enacting Game World Navigation. An excellent example of such a Helper is the owl in The Legend of Zelda: The Ocarina of Time, who sometimes flies in to steer the player to the correct places.
The direct use of Clues is as goal objects in either a Gain Information or Gain Ownership goal, for example to learn about Achilles' Heels. The player knows about the existence of the Clue and strives to retrieve the additional information by going to a specific location in the Game World.
A Clue may not necessarily lead the players towards actions they perceive as beneficial for the progress in the game. When this is the case, the Clue is used to promote actions, which the players would probably not otherwise initiate, in order to support the Narrative Structure or to promote Player Balance and Cooperation. This may be construed as a Red Herring pattern, used to trick players into actions that are against their low-level goals but that may be required to complete the game narrative or to put the players in positions so that they can reach the higher-level goals of the game. Clues to finding Easter Eggs are examples of luring players to perform actions that are not necessarily required to complete or win games but can rather be seen as Clues to Unknown Goals.
Clues can be used to provide the Right Level of Difficulty and Smooth Learning Curves, especially in the case where the game provides more Clues to the player if the progress is too slow. The Clues are often used to guide the player through the Narrative Structure of the game and create Tension by signaling the existence of dangers before they actually occur. This is especially the case in adventure games, which use Clues as the basic Resources of the player.
Clues are a form of Illusionary Reward, since they do not have to help players nor do they actually have to change the game state in a beneficial way for the players.
Instantiates: Indirect Information, Smooth Learning Curves, Resources, Illusionary Rewards, Outstanding Features
Modulates: Game World Navigation, Exploration, Achilles' Heels, Red Herrings, Unknown Goals, Levels, Alternative Reality, Gain Ownership, Imperfect Information, Narrative Structures, Right Level of Difficulty, Easter Eggs, Tension
Instantiated by: Helpers, Traces
Modulated by: Direct Information
Potentially conflicting with: Red Herrings, Emotional Immersion, Consistent Reality Logic