Sonic vs. Silver
From Sonic Retro
Sonic and Silver fight each other as the second boss of each of their respective stories in Sonic the Hedgehog (2006). For Sonic, the boss is listed as Silver the Hedgehog, while for Silver it's listed as Sonic the Hedgehog.
Having just liberated Princess Elise from Eggman's clutches by fleeing through Dusty Desert, Sonic and the human are walking through Soleanna Castle Town on the way back to the palace. Amy and Silver, also having just been to the desert (albeit the wrong part) in search for Sonic, finally spy him in a restaurant plaza, and Silver dives in to complete his mission for Mephiles and kill the Iblis Trigger.
The fight is often considered more difficult in Sonic's story than in Silver's; the CPU-controlled Silver can and does snatch Sonic out of the air mid-Homing-Attack with psychokinesis. Fighting Silver also includes a notorious impossible-to-escape situation where the CPU Silver can trap Sonic against a wall (or even against the sky or water) and simply keep telekinetically bashing the rings out of him until you lose a life. A successful strategy as Sonic requires the player to keep well away from Silver until the futuristic hedgehog is glowing green, having already picked up a brace of throw-able chairs or barrels. In this state Silver cannot block Sonic's homing attack, enabling damage to be dealt.
When playing as Silver, simply pick up the scenery at every opportunity and hurl breakable objects at Sonic. His Homing Attack is almost impossible to evade, so simply make sure you always have at least one ring, and keep breaking chairs over Sonic's head to chip down his health bar bit by bit.
Perhaps reflecting the gameplay difficulty of Sonic's fight, the subsequent cutscene seems to show Silver gaining the upper hand in the battle from both perspectives. Robotnik's floating platform re-captures Elise, distracting Sonic and allowing Silver to knock the blue blur down. A killing blow is only averted by Amy's intervention, standing in Silver's way and giving Sonic the chance to escape.
Like all boss fights, the S-Rank takes 30,000 points.
Beat Silver under a minute, and grab some rings to get the score to inch up to 30,000 (I'd say 7 rings is all it takes). Note that homing attacking away from Silver after dealing damage is a little tricky, as the computer might lock on to Silver instead, wasting your getaway time.
Of course, the real problem is avoiding Silver in the first place. The rather simple strategy is to run around the arena in a circle and wait for Silver to yell "HOW ABOUT THIS?!" Then you go towards him and deal the damage. He's not going to have much of a chance then.
The fight is rather infamous for its bugs, difficulty, and Silver's annoying "It's no use!" quote when he grabs Sonic. In addition to locking Sonic in an potentially infinite loop of attacks against the wall, one can glitch through the invisible walls (with the help of Silver or the Sky Gem) and trap Silver. This gives you the ability to traverse the entire Soleanna Castle Town Adventure Field, which was completely loaded up for the purpose of this boss fight (albeit people or interactive objects (the bridge's graphics haven't even loaded)). One can also get Silver to launch you up into space (no, we're not kidding. Space was added) while you're outside the invisible box. However, it is possible for CPU Silver to get through the invisible wall too, so be careful...(he can drown, though)