Sonic Chronicles: The Dark Brotherhood (2008) is a RPG Spin-Off from the Sonic the Hedgehog franchise, developed by none other than BioWare. Unlike many other spin-off titles in the Sonic (which typically receive mixed to negative responses), Chronicles was greeted with very positive reviews, at least official ones.A while after Eggman's latest defeat, the doctor is still missing in action, and is presumed dead. The peace doesn't last very long, though, as Sonic receives a call from Tails explaining that Knuckles has been kidnapped by a mysterious new group named the Marauders, who have also stolen all the Chaos Emeralds. Sonic then teams up with Tails, Amy, and Rouge in order to rescue Knuckles.A sequel was announced, but nothing's been seen of it yet.
Arson, Murder, and Admiration - After working together with Eggman, Tails seems to think of him less as an enemy and more as a fellow scientist, often commenting things like "Wow, I bet Eggman would love to see this!". If you call him out on it, he'll stop.
A Taste of Power - Sort of. Dr. Eggman has a lot of HP, a lot of PP and a ridiculously powerful and easy-to-execute special attack in Bombardment, as well as an instant kill attack against robots when used in conjunction with Tails. It's not a typical Taste of Power in that you don't start out with him, but he does leave the party about halfway through the game.
According to Word of God, the entire game was a Canon Immigrant, specifically of Knuckles' Archie Comics miniseries, hence all of the uncanny parallels between Shade, Imperatore Ix, and the Nocturnus to the comics' Julie-Su, Finitevus, and the Dark Legion. Ironically this is the closest game you'll ever get based on the comics.
Colony Drop - Once again, Angel Island ends up falling when the Master Emerald is stolen. Unfortunately, it crashed onto a city this time.
Console Cameo - A Model 1 Sega Genesis can be seen alongside an Egg Robo in the Metropolis level, and in the Kron Colony level, a Sega Genesis controller can be seen hanging from a beam.
Continuity Nod - Several. The game is even helpful enough to provide you with a mini-encyclopedia on the previous Sonic games in one of the menus so you can get caught up on any of the relevant Backstory that you might not have played before or had forgotten about.
Cowboy Bebop at His Computer: The codex claims that Sonic teamed up with Shadow to stop Eggman in Sonic Adventure 2. The only time Sonic directly worked together with Shadow in that game was to take down the FinalHazard, which was after Eggman was placed in an Enemy Mine situation.
New Game+ - Characters join your party at the same level they were at the end of the game. You're given the freedom to reassign all of their points used to boost their special abilities (except Sonic, since he technically never joins the party), allowing you to play around with new strategies. For some odd reason, although Chao Eggs regenerate, allowing you to collect any rare ones that you may have missed last time, rings don't, which means you have to depend on selling items back to the shops in order to make any more money.
No Ending - Combined with Sequel Hook. The game ends with Sonic and friends learning that Eggman has taken over the world. And then they thank Bioware for being awesome.
Obvious Beta: SEGA's contract with Bioware had just expired and they shifted their efforts to Dragon Age: Origins. As such, the game was released in a late beta stage, resulting in a bare-bones RPG with no sidequests. One of the most noticeable problems is the music and sound effects: most areas use placeholder Midi-format music of VERY low quality and pretty much all sound effects in battle are placeholder noises.
Odd Friendship - During Eggman's stint as a member of your party, he and Tails strike up a friendship.
One-Hit Kill - Spartoi, a special Chao, allows for a random chance to oneshot an opponent regardless of armor when the character he's with attacks.
One-Hit-Point Wonder - Built on the "Shedinja" model. Super Sonic and Super Imperator Ix both do massive damage with each blow, but if they don't take out their opponent in one turn (by not executing the Action Commands perfectly for Sonic, or by the player screwing up enough Action Commands for Ix), their health regenerates and they have to start over.
Operation Jealousy - Amy claims to have a new boyfriend named Dexter. He's never seen, and depending on dialogue choices, Sonic suspects she's making him up. If you're nice to Amy throughout the game, she eventually admits that she made him up.
Point of No Return - Multiple. Whatever you do, make absolutely sure you follow Eggman's advice and don't go into Metropolis unless you're sure you've got everything you need. Also, make sure to get everything in Metropolis before trying to recapture the Master Emerald. And after that, get everything in Metropolis Ground Zero before finishing the chapter, and then make sure you have everything from the Twilight Cage before starting chapter 10.
Precursors - Someone lived in the Twilight Cage before anyone else did, and Nestor calls them this.
Randomly Drops - Chao are obtained at random each time you get an egg. You could get all the best ones right off the bat or end up with crappy ones throughout the course of the game. Somewhat helped by the ability to trade chao with friends.
However, the randomness of the chao can be exploited by saving before checking the egg. Different chao are hatched every time you load the same save and check the egg.
Villain Ball - Way to announce your plans for world conquest right in front of your lieutenant who believed you wanted to simply return to Earth, Ix.
Well-Intentioned Extremist - Shade knows what she does under Ix is wrong, but views it as necessary to escape the Cage. Once she realizes Ix was using the Nocturnus to fuel his bid for conquest, she promptly defects from him.
What Could Have Been - This game is almost an Unfinished Beta - the one we have now is a very stripped down version of what was originally planned. Hackers have discovered that the opening cutscene was to be A LOT longer and have an actual battle. The music would probably be actually good instead of strangely retro soundly. But no! All of this is likely the result of Bioware being bought by Electronic Arts roughly a year before the game released, and Bioware completed enough of the game to fulfill their contract to Sega so that they could concentrate on Dragon Age: Origins.