Tails is ranked 2nd in the tier list. He has one of the best recoveries in the game, as his extra jumps allow him a lot more range and flexibility in his methods for returning to the stage. His Energy Ball Blaster allows him to fire energy balls that have infinite range and can be fired in three different directions (forwards, upwards, and downwards in the air), giving him strong stage control, versatile zoning abilities, and a strong edgeguard. He has some of the best instant-KO attacks in the game, including aforementioned up/down energy balls, the only projectiles with instant-KO properties in the game, as well as Rhythm Twister, one of the few instant-KO attacks that is not mapped to an up/down move.
However, he is not the strongest or most durable character in the game. He lacks the ability to cancel his momentum in the air, making him vulnerable to getting KO'd by moves that lack instant KO properties, like Knuckles' rock. His Electron Cannon has a slow firing rate, making it difficult to challenge another projectile user directly.
Regardless, his pros greatly overlook his cons, which puts him in the top tier.
Tails fires with his Energy Ball Blaster a single ball forward. A fairly weak attack at low percents, but at higher percents, its knockback is such that it will hit the opponent multiple times by bouncing them back into its path.
Tails uses the Rhythm Twister to spin around and strikes opponents with his tails. For some reason, Tails visually turns back on the direction he was facing when he initiates the attack, only to face the correct direction once the attack ends.