-Gunner vs Pikachu is a nice matchup, kinda even imo, Pika can beat us easily with bair mixups and gimps, since it acts as a semispike, if it lands while you're recovering, a stock is surely lost, Pika can combo like crazy and will stick to us with Quick Attack Cancel, leading to even more combo situations. If you have good defense and good aim, you can outcamp Pika and keep him at bay, to the point where he won't be able to approach at all.
I have a match vs a Pika, who's my crewmate, check it out:
-There's a video where Esam explains that priority on smash doesn't exist, what does exist are trades and clanks, if i remember correctly, only on the ground will clanks occur when an attack is 9% stronger than the other, it will beat it, also, spindash mechanics are button mashing dependant, the more mash the sonic does, the more damage spindash will do, in fact, if spindash isn't mashed, most attacks will clank with it, like a no charge NeutralB, Dtilt will beat all the unmashed spindash too, since it does a lot of damage, also, Sonic's SideB full charged will do more damage than his DownB, that's why they use it most of the time, when fully charged, it will beat many of our attacks, only Fsmash, SideB and full Charged Shot will beat it on the ground.
There's another rule when trading, if a ground vs air trade is made, both characters will take the attack, and air vs air, also both will take it, that's why our Nair can trade with spindash, but be aware, Sonic's SideB fully charged outdamage us, so, trading with Nair isn't worth, our best bet would be Bair but is really hard to land it on Sonic's spindash size and on reaction, because we have to turnaround and jump, also, don't forget those spindash cancels and baits, trully, an annoying move.