Mission Mode is a gameplay mode is available exclusively in Kingdom Hearts 358/2 Days. Through Mission Mode, one to four players can compete in missions across the worlds. Mission Mode uses the Nintendo DS's wireless capabilities to compete with other players, but all players must have a copy of Kingdom Hearts 358/2 Days. Items collected and character growth in Mission Mode carry back to the save file the player selects at the start. Guest Play can also be selected, where upon the player is given preset items instead of those obtained in Story Mode.
Solo play was a more developed feature in the English releases of the game. In the original Japanese version, Mission Crowns -prizes from completing missions- are only awarded in multiplayer mode, whereas in the English version, they can be obtained in solo play. Also, the selection between solo and multiplayer was made more clear cut in the English release. Unlike the Japanese version, selecting "Mission Mode" in the English version offers a choice between solo and multiplayer on the main menu. The Japanese version instead brings the player straight to the Wi-Fi group menu, but the player can continue alone without other players.
At first, the player only has access to thirteen characters, all members of Organization XIII. However, as the player progresses through Story Mode, an additional six secret characters can be unlocked.
Right from when a player accesses the main menu, they have the option of playing either the main game, Story Mode, or the multi-playing Mission Mode. After the player selects the "Mission Mode" option, they are taken to the Character Selection Screen. They are given a chance to view the stats of the character they choose, which are each represented graphically on a scale from 1-10, just before being taken to the Menu Screen. The player only has access to Organization XIII to begin with, later gaining access to new characters as they play through Story Mode.
At the Panel Customization Screen, players have the ability to select weapons, items, spells, and abilities that are to be used during competitive gameplay. It should be noted that players will also have access to items gained during Story Mode. It is then that each player is taken to the Mission Select Screen, the last screen to appear before gameplay begins.
At this last screen players select a world and a mission they would like to play from Story Mode that took place in that world. It should be noted that missions are made playable once their respective Unity Badge has been collected in Story Mode.
During actual gameplay, players work toward the same goals that Roxas would in Story Mode, collecting Mission Points along the way. Players can attack each other, stealing the targeted players' Mission Points as a result. While the Mission Mode is mainly a way to battle enemies with friends in an allied setting, its true intention is competition due to its friendly-fire format. Just as in Story Mode, a mission ends when the Mission Gauge is filled to the first, or sometimes only, marker. However, in Mission Mode, extra Mission Points can be gained by getting to the RTC in a certain amount of time.
At the end of a mission, the results of gameplay are displayed. The characters selected for play appear in the thrones of Where Nothing Gathers, the thrones' height determined by the number of Mission Points. Places are awarded as first, second, and third, each displayed by a gold, silver, or bronze crown respectively.
Mission Crowns are earned after completing missions. They can be redeemed at the Moogle Shop for various rewards.
An especially new feature in Mission Mode is the ability to chat with other players. During a mission, players can message each other via stylus or in-game keypad. Various colors of text can be used, adding to the fun of this feature. From saying hello to requesting help tackling a boss while a friend is busy with another target, messages are displayed on the Nintendo DS's bottom screen along with Mission Objectives.
In general, the Heartless and Nobodies fought in Story Mode will be in their respective places in Mission Mode, though some enemies have been removed when not integral to a mission, such as the Jumbo Cannon in Mission 73: Defeat Heartless in the Games, or Xigbar in Mission 61: Vanquish the Heartless Threat. Furthermore, enemies generally drop items much less frequently in Mission Mode. While not an actual change in game mechanics, the Saïx and Riku bosses were replaced with shadowy Anti-Saïx and Anti-Riku bosses, to prevent confusion between the bosses and the playable Saïx and Riku. The enemies in Mission Mode are now three to four times stronger than they are in Story Mode on default settings, and can be made even more powerful and dangerous through tweaking Mission customizations.
These poses are used whenever a character is victorious in the Games at the Olympus Coliseum.