Originally released as a Japan-only mobile title, Re:Coded is the second Kingdom Hearts game to be released for the DS, and the first one to take place after Kingdom Hearts II. After Birth by Sleep so neatly set the stage for what was to come, you might think that Re:Coded might also have some critical revelations in store, but it's more of a weird diversion than anything else. If there was any Kingdom Hearts game I would encourage players to skip, this would be it.
Re:Coded finds Mickey, Donald, Goofy, and Jiminy Cricket back at Disney Castle, trying to organize Jiminy's journal (which served as the in-game datalot/bestiary in the first two games: yes, this is the level of minutiae into which we are now plumbing). Noticing a mysterious message in the journal that reads "Thank Namine," as well as another that reads "their hurting will be ended when you return to mend it," the group decides to encode the book in data and analyze it further to get to the bottom of this (just... bear with me here). In order to do this, Mickey creates a digital facsimile of Sora, whose job is to destroy the bugs that have infested the digital book and follow an approximation of the real Sora's journey from Kingdom Hearts. Only by doing so will the characters find out the truth of what Namine did to help Sora in Chain of Memories, and learn who Terra, Ven, and Aqua are... all of which is information the player already knows about, and isn't nearly enough of a plot justification for an entire video game.
...Yeah, I don't really care for this one. I don't know if the rumor about Nomura being drunk when he pitched the concept for Coded has any truth to it, but I wouldn't be surprised. Putting aside the fact that Re:Coded only really exists to fill in a single plot hole, and it's already information the player knows about and could have been explained to Sora and company in a minute-long conversation, there's just no incentive to care about what happens to Data Sora and the Datascape. Re:Coded tries to create some tension and drama by saying that the digital simulacrum have hearts of their own, but this is a flimsy excuse at best. If not for the fact that I'm pretty sure Data Riku is going to show up in Kingdom Hearts III (yes, there's a Data Riku as well as a Data Sora, because of course there is), I would honestly recommend skipping this game entirely, unless you're committed to experiencing every Kingdom Hearts game. There's just too little of substance here in the grand scheme of things.
Fortunately, the game itself fares a bit better than its predecessor, 358/2 Days, in the gameplay department. The Command Deck system from Birth by Sleep is back, for one thing, only now Sora has a kind of Crystarium-esque levelling board that lets him unlock new abilities, and even toggle certain mobility options on or off depending on the player's preference. The controls are still a little rough due to the DS's limitations, but it works a bit better here because Re:Coded is more of an action-puzzle game than a straight action RPG. Oh, sure, there's still real-time combat against enemies and platforming (with a D-pad in 3D environments... joy), but the presence of bugs in each world sees Sora performing a number of different tasks in order to clear them and navigate each world.
Each world also has a unique gimmick that alters their playstyle dramatically: early portions of Traverse Town, for example, turn into a 2D platformer, while Olympus Colosseum manifests as a turn-based RPG, Wonderland as a top down stealth game/bullet hell shooter (yes, really), and so on. There's even a neat return trip to Hollow Bastion where Sora is without his Keyblade, and has to make Donald and Goofy do all of the work for him. It's interesting to see the developers experiment with different gameplay styles, and honestly, if you look at Re:Coded as more of a Kingdom Hearts-themed minigame collection than a canonical, mainline entry in the series, it's not half bad. Unfortunately, that's too little, too late in my estimate, and Re:Coded emerges as the weakest entry in the series to date. You can watch the cutscenes included in the ReMIXes if you so desire.
Still, the ending for Re:Coded does provide a tantalizing hook. In a conversation between Mickey and his Master, Yen Sid (the wizard first introduced in Kingdom Hearts II), it is revealed that, now that the Heartless Ansem, the Seeker of Darkness and the Nobody Xemnas having been destroyed, the way is clear for the two halves to reunite and for Master Xehanort to return. It seems that Mirror Universe Spock has a sinister plan that will soon be set into motion. With that threat looming, Yen Sid bids Mickey to bring Sora and Riku to him: to train them to earn the Mark of Mastery and become true Keyblade Masters.