Kingdom Hearts Re: Coded is a remake of Kingdom Hearts Coded that was released for Mobile, only in Japan. The game takes place after the events of Kingdom Hearts II, when Jiminy's Journal (where the events of Kingdom Hearts I & II are recorded) gets infested with bugs. In order to decode the information in the journal and debug it, King Mickey, Donald, Goofy and Jiminy Cricket digitalize it. With the help of a digital Sora, recreated from the Journal's code, they start exploring the Worlds in the journal to reveal what is missing.

Leveling-up and gaining abilities in done by installing chips and unlocking Support Abilities and Command and Accessory expansions in the Stat Matrix. The Matrix also includes Cheat Tuners that are used to change gameplay elements such as game difficulty, item drop rates, etc.

In addition to the regular Action RPG elements from the Kingdom Hearts series, the game includes gameplay elements from other genres. In some Worlds or Boss battles the game mechanics change completely. Some are Side-scrolling or third-person shooter levels, and even turn-based RPG.

After reaching a certain point in the game, each World can be revisited to try and get higher scores, find new areas and do some side quests.