Sonic Chronicles: The Dark Brotherhood is not quite Sonic's answer to Super Mario RPG, but it's by no means bad.
The reality is, as it often is, somewhere in the middle. There are a number of areas that could be marked as having room for improvement within Sonic Chronicles. The game is a fair bit on the short side compared with other titles available for the DS; the story is, on the whole, lackluster, and not too engaging; and the background music can be at times atrocious.
Yet, on the whole, I can't help but feel that despite all of the flaws in the game, the fundamentals are nonetheless sound. If a sequel was developed that fixed the problems and built off of the foundation established in this game, Sega could have a real groundbreaking winner on its hands. Thus, if the test of whether or not a game meets the acceptability bar is set to be whether or not its player would like to see more in a sequel, then Sonic Chronicles definitely passes in that regard. As this game stands, however, it's pretty good, but not quite great.
Probably one of the game's biggest strengths is its surprisingly excellent attention to detail as far as the Sonic universe is concerned. Already established fans of the Sonic series will be assuredly pleased with this aspect of the game - Bioware has quite clearly spared no expense (and likely worked very close with Sega) to ensure that the game is completely and fully correct as far as Sonic canon is concerned. As for the obvious question of whether or not the framework laid out by canon translated well to an RPG model, the answer is yes - to a point.
Ironically, however, perhaps one of Sonic Chronicles biggest downsides is that it perhaps pays too MUCH attention to Sonic canon. The game includes everything that one would expect from past Sonic games: loop-the-loops that Sonic can complete, rings, Chaos Emeralds, Eggman and his robots, G.U.N. - you name it, it's probably in the game in some form or another. The game is a veritable smorgasbord of Sonic elements, and while it's commendable that Bioware made such an amazing effort to give Sonic fans everything they expect, I can't help but feel that they could have been a little more selective in what was and wasn't included.
One of the biggest strengths of Super Mario RPG, probably the best game to compare Sonic Chronicles with, was its willingness to throw out the parts of Mario games that didn't really work in an RPG setting, and to replace them with elements which worked much better, despite being totally non-canonical as far as the Mario universe was concerned (Mallow, Geno, Smithy, etc.). I think the same could be applied to Sonic Chronicles, as well - stuff like the loop-the-loops seemed like a cute nod to old-school Genesis games, but otherwise seemed tacked on for the most part, and didn't really seem like a necessary, integral part of the game. Another annoyance was the fact that there was only a set number of rings in the game to be collected, and any others someone might need had to be collected indirectly by selling items (which, fortunately, were retrieved after every battle).
The story could also have used some improvement. While it wasn't bad, it wasn't really engaging, abounding with twists and turns, and exuding an epic feel in the way that the story of a truly great RPG might be. When I completed the game, it felt as thought the story should have just been getting going and I should have been reaching the "and now it gets good" part, but alas, no such luck - the game was over. Again, I felt that the game suffered from its tendency to stick too closely to canon as far as the story went, as well.
There were some new aspects introduced that hadn't been seen before in the Sonic universe (which I will not detail out of my desire not to provide spoilers - there ARE certainly things to spoil), but on the whole the story seemed a little too safe. Yet, at the same time, it seemed like it could have been more safe still; it was as if Bioware (or Sega - I'm not sure who had the largest say regarding the story) was unsure, even as they released the game, of whether or not they wanted to keep it solely within the established Sonic universe or whether they wanted to let loose and show the players Sonic and his world as they've never been seen before. In my own humble opinion, I think they would have been better served doing the latter.
The selection of characters in the game is pretty good, and provides a pretty representative sampling of the Sonic universe. There are eleven playable characters in total, and only one of them is a character newly introduced for this particular game. The character balance was good as well - while there are a few characters who are pretty useless once better characters come along, there isn't really one single "best" selection of four characters that dominates all the rest; many have their own strengths and weaknesses.
The game also gives a nod to other Bioware games such as Mass Effect by including a dialog system where you can choose what you want Sonic to say to someone. This system, however, seemed much less robust than it was in Mass Effect, and the only real point gained from it is the ability to ask relevant questions. However Sonic responds to something is largely immaterial with respect to the grand scheme of what happens in the game, and that's a point that I believe could be improved in subsequent games as well.
The gameplay - always the core of any game - was well-done enough in its own right. It's a fairly standard RPG fare - your character can be moved around in an overworld, and in that overworld you can run into enemies (literally run into them, that is - that's how battles are started). Once in a battle, you have your standard attacks, your items, your "defend" command, your "flee" command, and your special abilities. In Sonic Chronicles, these special abilities are called POW moves, and take up PP (POW Points, I suppose). Some POW movies are solely performed by the initiator of them, while others require two, three, or even all four members of your party to participate.
Bioware seemed to take notes from Elite Beat Agents with regards to POW moves - when carrying out or defending yourself against any POW move, circles appear on screen that you must either tap at the right time, follow with the stylus, or tap eight times within a time limit. If successful, the move will either be more powerful (if it's your attack), will succeed (if it's a support move), or will have damage lessened (if it's an enemy's attack). This is a fairly nifty way of doing things, and it adds a fair bit of interactivity, although I thought that it might have been better to emulate what was happening on screen more than was done - as it stands now the circles seemed to be off in their own world for a little bit, and fairly unrelated to the action being performed.
Probably one of the biggest surprises was how relatively poor the audio in the game. Ever since their Sega Genesis days, Sonic games have always been known to have superb music, so it was a bit of a letdown to see that not carry over into Sonic Chronicles, especially given that many other Bioware games as well had excellent soundtracks. There were some notable exceptions that were great tracks, but on the whole the background music was only lackluster, and was at times just downright bad. The sound effects could have been improved, as well, although they were only ever mediocre - never quite crossing the threshold into "bad".
But once the chips are down, there's really only one question to which gamers really want the answer: is the game fun? And the answer to that question, despite all of the game's drawbacks, is yes. Sonic Chronicles is not perfect, and it's not the game that will convince Sonic detractors that they should rethink their position, but it's nonetheless a solid first step for hedgehogs into the land of RPGs. If you're a Sonic fan, then you definitely should pick this game up, and if you're a DS owner looking for an RPG, then you also ought to give this game a fair look. I understand that the next edition to Sonic Chronicles is already being written, so I for one am looking forward to it - I earnestly hope that Bioware can successfully use the foundation they've built in The Dark Brotherhood to push the next game across the threshold of greatness.