Anti-airs seem to be really strong in Jojo's, which I must say that I like. It forces footsies more to the ground, and forces the opponent to work/bait/trap a jump-in rather than getting it entirely for free. A huge breathe of fresh air from playing games like IaMP, SWR, and MBAC where you actually have to work much harder for your anti-airs than you do for your jumpins, taking risks for even half-decent anti-airs only to be punished for ridiculous damage if you were anticipated.
Unfortunately they aren't always intuitive. I use to think that activating Avdol's stand and doing back+A2 would probably be a guaranteed anti-air, but in practice it's much too slow to anti-air short jumps. It is, however, an incredibly good anti-air when the opponent airtechs into you, or you juggle oddly, or the opponent highjumps/doublejumps/whatever. But it's just much too slow to do on reaction to a shortjump.
Instead, Avdol and Midler can anti-air with their qcf+S moves. Midler's is a bit better IMO. But both work wonders since they can't be airblocked, are super fast, and have enormous hitboxes.
R.Soul and Kakyoin's are complete no-brainers though, since almost everything they have works as anti-air in some way or another. Incidentally though, R.Soul's qcf+A projectile and quite a few other projectiles can be used as anti-air in some cases, which really reminds me of Chun-Li, though it can be airblocked. But even better, Midler's qcb+A cadillac is an awesome prevention tool just like R.Soul's qcf+A projectile. However, I'm pretty sure the cadillac can't be blocked from the air and it has a incredibly gigantic hitbox, perfect for anti-airing on anticipation.
This is really strong for characters like Midler because they have such formidable ground games too. Quite a lot of her ground pokes are simply too good for players to reliably beat out on anticipation, and it's not likely to punish them on reaction due to the free-cancel rules in Jojos. Thus, even if you do anticipate one of her ground pokes and try to jump over it, she can just cancel it mid-animation into her qcf+S for a quick anti-air, and sometimes even as a counter to a ground counter-poke.
Oh, how I love this game.
One of the most amusing anti-airs I've found so far though is Mariah's. If she sets her stand on the ground you pretty much have to get rid of it somehow which potentially leaves you open while you're attacking it. You can't roll through it or she will throw you, and you can't jump over it or she will anti-air you. And even if she can't anti-air you, if you do a jumping attack then she can simply block and then pushblock you into the Stands electrical outlet. Far too beastly, I must say. Of course, empty jumping over the stand doesn't work either because then she can just go back to anti-airing you as normal, or waiting until the last moment to c.A1 you into the outlet. Basically, as soon as she has the outlet out you have to get rid of it or avoid it, there's not much else you can do.
Out of the characters I play, all of the have reliable anti-airs. I probably wouldn't play a character that didn't, though. Hence why I most likely gravitated to R.Soul first and foremost.
Oh anti-airs, how I have missed you so..
Basically, the game really does force you to be patient, tactical, observant, and use reaction more than anticipation, which I find extremely lacking in most of the modern games that I've played lately. I think SS5sp must be the only other game I've played lately that is also really patient and tactical, and that rewards much more for reaction than anticipation.
Of course there's nothing wrong with mindless rushdown and guessing games every now and then. But to me those types of games feel like a cross between a grind and a numbers game, rather than something fluid and strategical.
The concept of fuzzyguard exists in Jojo's. Many characters can use this to their advantage for a quick high/low, exactly like in Meltyblood. Except, in the case of Jojo's, fuzzyguard isn't performed with a doublejump. Instead, you perform a jumping attack, land, and then perform a while-rising jumping attack to hit the opponent high twice in a row. If they block low after the first jumping attack then then second jumping attack will hit them.
And, the reason this hits them is explained in the above linked video.
But I'll just explain it here a bit too. Basically, when you block something, you are forced to remain in that block animation until blockstun ends, or until the next attack connects. So if you block high, you will remain standing, and so you're pretty tall until either blockstun ends or you block/get hit during blockstun.
Therefor, even if you can't normally hit a crouching characters with a while-rising jumping attack, you most likely can hit a standing character with that attack. Because of this, what happens when the opponent incorrectly blocks a fuzzyguard is, first they block the jump attack high which locks them in a stand block (tall) animation for a moment, then they push down+back to block low, only to have the second jumping attack hit them in the head while they were attempting to block low. And once they are hit they instantly move into crouching hitstun state.
Characters like Chaka and Joseph can do such things by just jump attacking, landing, then jump attacking again on the way up.
Characters like R.Soul have a much more devious ability. Technically R.Soul's j.S won't hit a crouching Mariah or Iggy, but if they are first forced to block a j.A high then they will be standing tall enough for the j.S to hit regardless if they block it high or low. If they block it high then they again are put back into a standing blockstun state which allows R.Soul to potentially do a while-rising j.A which definitely only hits standing characters.
That let's him basically do two fuzzyguards in a row, kind of like something out of MeltyBlood, except much more effective.
And of course the mixup is that he could do a low instead of either fuzzyguard, such as; j.A1 c.A1 // or j.A1 j.S c.A1
The good news is that the defense for this is to, of course, anti-air them. Which as explained in the first part of this post is really reliable. Though another good defense to this is simply pushblocking, since it puts you out of range to do much else.