Portal (Gameplay element)

Portal is a gameplay element introduced in Kingdom Hearts 3D: Dream Drop Distance. They are a special type of communication system that allow characters from various Dream Worlds communicate, sometimes, even transport from one version of that world to another.

Link Portals
Link Portals are a type of portal that can be found in all Sleeping Worlds. They give special challenges for the protagonists, Rare Nightmares to battle, other Spirit's party or even allow them to battle stronger versions of the bosses, rewarding the player with Droplets, Dream Pieces, and other prizes if they are completed. Each portal belongs to a "player", usually named from a Final Fantasy character, like Auron, for example.

Mechanics
Link Portals are seen in the bottom screen map as pink glowing dots, but they can't be seen in the top screen. Although they can be seen in the normal map, they can only be accessed in the zoomed-in map. When the player steps in the point where the portal is located, a box with the name of the owner, the difficulty rank, and a symbol of the type of challenge or the Spirit Party of the portal will appear in the map. If the player touches that box, another one with more details about the Link Portal will appear in the top screen and one asking if the player wants to open the Link Portal in the bottom screen. After reading the details, the player can choose "yes" or "no" to decide if the Link Portal will be opened.

There are four different types of Link Portals:
 * Battle Portals: These portals give the player a series of Nightmares to battle, according to another "player" Spirits. It also gives a "Bonus Objective" to be accomplished during the battle like deefeating all Nightmares in a set time limit or doing a number of Flowmotion attacks. After opening the battle Portal, the word "start" will appear. After cleraing the portal, either accomplishing the bonus objective or not, the word "finish" will appear, followed by the results of the portal, telling the player what was obtained. There are three prizes: a "Point Prize", consisting of Droplets, an "Other Prize", like a Dream Piece, and a "Bonus Prize", obtained only if the bonus objective was completed.
 * Friendship Portals: These portals allow the player to temporarily borrow another player's Spirits. If this portal is activated, the player Spirits will be temporarily exchanged for the Friendship Portal Spirits, which come with the Link Gauge full and the HP gauge replaced by a time gauge divided in four segments that deplet over time. When that gauge runs out, the Spirits are exchange with the player Spirits again.
 * Special Portals: These portals pits the player against Rare Nightmares and give even better prizes, like Dream Eater recipes. There are six Special Portals for each character in each world, with the exception of The World That Never Was, that has only three. Only one will be open in any given world per drop. After beaten, they can not be entered again unless the player completes all of them. After all are beaten with one character, that character will receive the End of Pain Keychain.
 * Secret Portals: These portals are unlocked after beating the game. In them, the player can battle stronger versions of the bosses of the world they are in. After all are beaten with one character, that character will receive the Unbound Keychain.