I played the first Golden Sun for the GBA and felt, while it wasn't the best portable RPG for that system, it had some great innovations such as the Psyenergy and Djinn systems which the game revolved around as well as challenging puzzles and sidequests. Now the DS sequel still holds these intact, but this sequel is lacking in substance that made the original games so popular.
Golden Sun runs like your typical RPG: roam the world map, enter towns, buy items, collect treasures, fight monsters etc. Anybody who knows this genre knows what to expect here, but of course I need to go into the aspects that make this series stand out from the crowd. Psyenergy is basically the game's magic system, but is also used outside of battles for puzzle solving and just generally getting from A to B. The Psyenergy 'Move' for example pushes wooden blocks out of your way or to provide a stepping stone on the next level, 'Grip' allows you to propel yourself across a gap by grabbing stalactites or setting cogs in motion, and there are many more that you recieve in game, and it becomes pretty clear what each Psyenergy is needed for certain situations, allowing for smooth gameplay.
The Djinn system also makes a return, and as with Psyenergy nothing changed for worse. For those unaware, as you go around the world you collect these Pokemon-like elemental creatures and assign them to characters. Each Djinn has different abilities in battle. Once used they go on standby and can be used to summon powerful entities to deal heavy damage to your enemies in battle, at cost of being unuseable for a short while and a heavy decrease in the character's stats. Like I said, this system is impressive and it's a challenge to find Djinn around the game world, since some require completion of puzzles and a diversion from your main path. It provides a balance to gameplay and shows off the most impressive bits of this game.
However, the rest of the gameplay is RPG-standard and doesn't really go outside the box other than those aspects mentionned above. Dungeon puzzles do provide a challenge but towards the end of the game they really begin to drag and become boring. There also seem to be a lack of sidequests here, except when going out of your way to find Djinn- something the original games had in Spades.
I'd also like to comment on the graphics here. These are very good for a DS game. It's great seeing characters and buildings rendered in 3D. They are strongest in the battle cinematics such as during summoning, which take up both DS screens and are truely fascinating to watch. Music on the other hand is ok but certaintly not memorable, though it's nice to hear some tunes from the previous games incorporated here.
The plot and characters, which aren't the strongest feature of the games, failed to impress me here. We follow the children of the original characters from the first two games: Matthew (son of Issac), Tyrell (son of Garet), and Karis (daughter of Ivan), among others that join you later on. Yet the game doesn't thurst our protagonists into the main threat of the game until at least halfway into the story. The reason why Matthew and co. leave on their adventure? To collect an item which at best serves as a tangent to the eventual threat of the world. Furthermore to get this item you need to go on various quests and take more tangents. At worst this seems like deliberate padding while the designers tried to think of a decent world-destroying problem for this generation of heroes. The ending isn't remarkable and left questions unanswered, though this is more likely because they put in a sequel hook.
The characters suffer the same problems as the GBA prequels in that they are incredibly lacking in personality. Matthew is mute with his only personality being the input actions (more on that later). Likewise, Tyrell serves as comic relief and the slightly dopey member of the team, which makes him slightly more interesting than the others if not being annoying sometimes. The others unfortunately fall into the same flatness, either being boring or having interesting backgrounds which are all but ignored in favour of getting the main story going. It's not helped either that Matthew and Tyrell's designs make them so similar to their parents in the original games they might as well have been cloned. There are camoes from some characters from the previous games but at least the focus isn't always on them since this is a separate adventure of course.
I think so much more could've been done in enriching the story's depth, but I suppose they have little to work with considering it revolving around the issue of alchemy (which has been solved more or less). Nevertheless I still got 30 hours out of the gameplay and it kept me interested at least through the puzzles. It's a good RPG, but not a fantastic one.
(Also on Ciao under the username Anti_W)