The Black Knight - The Shining Armor, or the black soot? satoshixhikari here, the only reliable reviews around.
Sega's new project, The Black Knight, many people would expect another reason to ditch our spiky, blue hero - this is not the case. An unexpected improvement from Secret Rings, Sonic is no longer limited to the rails, being able to move semi-freely around the stages (you'll still have to get used to looking backwards). The sword mechanic works well, and while there's waggle, it isn't Red Steel. Swing here and there, it's really simple - oh, and the game's fast... FAST. SPEED. The homing attack is still intact as well.
Enemies vary 'round size, endurance, strength, and numbers. Every stage has every bit of armed enemies trying to kill you every way possible (now, without the sword, Sonic would have a slow time killing them all). Bigger enemies require head-to-head combat, but it's not really hard if you have the Special Gauge full.
Bosses are creative and fun, but aren't much trouble if you're skilled in the blade.
Multiplayer is described to be a wag fest... yeah, pretty much, but waggle is better that broken. Online co-op is very entertaining, and the unlockables are very rewarding if your ego's big. Missions are optional now, and it's quite fun to see you smite the villagers.
Stages are well 'rounded, some being bland, most are innovative. The open world view is very much like Legend Of Zelda, which is interesting enough. The voice acting isn't bad (really, it isn't), and the cast of characters are unique. Playing as Knuckles, Blaze, and Shadow is, again, fun in trying them all and their different styles.
Overall, Sonic and the Black Knight is considerably the best game so far in Sega's career - not the BEST, but it's incredibly solid.