I think you have the names confused. Re:Coded was originally a mobile game in Japan, but it was remade for the Nintendo DS.
Re:Chain of Memories was originally a Gameboy Advance game that was remade for the PS2, so I think you're thinking of that one.
It's a good game, but the gameplay is a bit different from other Kingdom Hearts games. It's card-based, so instead of blindly mashing the X button to hit your enemy, you'll use up an Attack card every time you do so. You can use up to three cards at once for combo attacks. If an enemy uses a card with a higher number than your own, they will block you, and if you use a card with a number higher than theirs, you'll break through their attack or block.
It takes some getting used to, but I enjoyed it. It will fill in some of the story between KH1 and KH2 pretty well, so if you don't intend to get a PSP or a DS and the Kingdom Hearts games on those systems, I'd suggest playing it.