I don't play ssb and it abilities from that game shouldn't be included as knuckles isn't in ssb if I am correct.
But if we're counting smash moves the only real thing is a strong punch that throws you far. (I also saw the whole speed punch donkey Kong has) and Knuckles could easily avoid both. Knuckles would see the explosive punch get hit once or twice and then back off because he has the speed to do so.
Also in tails vs luigi. Tails didn't use a quarter of his abilities (or items) either. Tails has a jet with homING misses and the jet can go as fast as sonic is willing to go. Tails had many more weapons like Luigi thar he didn't use.
Luigi could use his tornadoes to throw the plane off balance and make it crash. He could also use his lightning or telekinesis abilities.
But sonic doesn't actually run at the speed of sound.
Sonic is WILLING to run under the speed of sound. It's a theory saying sonic wouldn't go as fast as he can because he's not willing to. But just because he doesn't run at the speed of sound doesn't mean he's not faster then a tornado. I also even said the plane goes under the spesd of sound so idk why you even poibted that out.And person McPherson there was a theory about that I don't remember though.
um….. why? if he needs to you know save the world wouldn't he just go the speed of sound?
Because the speed of sound would hurt the area around him. If he went the speed of sound all the time he'd hurt the wild life and he could even hurt himself. His main goal is to protect the wildlife and the people. If he went the speed of sound he'd tear up grounds, ruin homes, if someone was close to the speed of sound they're ear drums could explode. He'd also hurt himself by hitting things all the time (inside Eggmans labs ect.) Sonics main goal is to protect the things around him.