For starters @
Fortune
, Sonic's down special can either be released from one charge or many charges, it automatically releases after approximately 1 and a half seconds if you maintain a fast speed of mashing. The number of times you mash determines the speed of the spin charge. You can also b reverse the spin charge. This is what the charging animation looks like.
The charge up has a hitbox that continously applies hits and can draw opponents in if they don't SDI properly. The released spin charge has a continuous hitbox that deals good setup knockback to opponents under 100% (once you get past 100% it's very difficult to land followups after spins) If you pull the other direction on the stick you will enter the turn around animation which has a seperate hitbox, if you do this on an opponent's shield that means 3-4 hits of pressure on the shield.
Sonic will continue to move to the right a bit before he accelerates in the other direction. You have two followups from a spin charge; a jump or a cancel.
Jump Cancel
Press any jump button or up on the stick to leap out out of the grounded animation into a special spin charge jump animation.
This has its own special hitbox that can follow people up in the air for a secondary hit which can often lead into aerials for a kill. For example here's a combo I landed the other day:
The Skid Cancel
The cancel cannot be used out of a turn around and I find it a bit useless in most situations as a jump is usually safer but never the less its an option. Hit a shield button to enter a skid animation and quickly stop the spin charge.
Shield Pressure
Good shield strings are usually followed up from a turnaround spin charge the a jump cancel into an aerial, you can use this as a bail strategy or apply more pressure. I generally follow up with a dair from a turnaround but position myself in a way that I cannot be grabbed after the string. This is still risky however and can be interrupted midway. I wouldn't say that down special is the best choice for shield pressure, unless you charge it initially on the shield, I'd be looking more at the Somersault (side special) for large amounts of shield pressure.
Kill Combos
At low percents Sonic can link lots of things from spin charge. Generally a hit > turnaround > jump > aerial hitbox hits > aerial is the way to follow up.
At mid percents the aerial hitbox will often not hit or hit the opponent too far way for a followup, in these situations I'd usually advise you to go for a kill move prior to hitting the aerial hitbox of the spin or go for a spring > aerial followup after the hit.
At high percents Sonic has a lot of trouble landing anything out of spin charge. You have limited options here and the most reliable setup is simply spin charge > nair which works at most percents provided the nair comes out instantly after you hit with the spin.
Spinshot
You should also be aware of the spinshot, which is, funnily enough, an advanced technique from Sonic speedrunning that has made it into Project M somehow. Hit down special in the air then instantly cancel it into a double jump. This is a long distance recovery option which can also be used for followups from grabs or aerials.
(Note that it goes further than this, I just took the screenshot here to illustrate where the jump begins.)
I hope this helps, I've been playing Sonic for 10 months now and have gotten some consistently good places in tournament so I have faith you can find some valid points in this post. Hope to see you around.
