Either Win/Lose an Online Match, then go to local replays to Battle Log and press  to upload the replay.

Simply go into Ranked Match with a boosting partner, then custom search and set the matches to 1, pick anyone, and then win. If anyone has an issue getting this, I suppose you can go to the trading thread to ask for help. (Due to most online communities being a ghost town).

Mahrahia’s stand is mostly a magnet (not to confuse with Magneto), in which case, pressing the Stand button () (and in any direction) will show it and if it hits the opponent (not blocked), her stand power will be leveled up, hit it about 7-8 more times to Max it out. This can be easily earned in Training Mode.

Although this doesn’t mention the character, this is suited towards Alessy, in which his stand has the power to make the characters into children (except Joseph). Pressing QCB and any attack will make them small, his supers (either QC B/F [Quarter Circle Back/Foward] and 2ATK) also has the same effect, you must KO Alessy while they’re in this form.

Stands have their own bar, which is kind of like a guard crush gauge, once depleted, you will be open to an attack, simply put, once you opponent is low on life, Stand Crash and then KO them.

Pretty simple really, as this will be a gimme achievement to all. Just KO the opponent using either regular or special moves.

Another simple one. Once your opponent’s life is low, perform a Super Combo mostly done with QCF+2ATK buttons. (All characters have more than 1 super, check the command list for details).

Now this is one of the difficult achievements I mentioned, although this can be only done by playing the “Story Mode” with either Jotaro/Joseph/Avdol/Kakyoin/Pollarneff/Iggi as you race against the clock to beat N’Dool without getting hit from his water stand from start to finish. Although the patterns of his attacks are mostly the same, sometimes they’ll go in different directions/paths and you might get sidetracked, other than that, with a bit of practice, this will be easier enough, Here’s a video with Jotaro & group best suited to make it quicker, note that some dexterity is required and results may vary.

www.youtube.com/watch?v=BlIbvpgoApE

Time Freeze is one of Jotaro‘s and Dio’s/S.Dio’s super moves which require 3+bars (2 for S.Dio) of the super gauge to pull it off, of course though, your opponent has to activate it first then at any time during the Time Freeze super, you can counter it with your own. Press the necessary inputs down below in sequence, but not all at once. You can also get this more easier in Training if you record the 2nd player input, then play it and you pull the same super move.

Jotaro:  > > > > 
Dio:  >  >  >  > 
S.Dio:  >  >  >  >

A Blazing Fists match is kinda like clashing, but it requires the use of both you and your opponents’ stands and certain special/super movers for it to trigger. Easier way is both you and your opponent to be Polnareff, Activate their stands, be about halfways across the screen, then tap  for a special move, this may take some tries to pull it off right. This too can also be earned in Training with the 2nd player record/play feature.

Simple enough, just play all the 22 Characters listed here and win a match with each of them in Local 2P versus within 1 round settings, max handicap, and max super gauges too to pull of quick powerful supers.

1. Jotaro
2. Joseph
3. Avdol
4. Kakyoin
5. Pollarneff
6. Iggi
7. D’bo
8. Alessy
9. Chaca
10. Midler
11. Mahraiah
12. Hol Horse
13. Hol Horse W/Voing
14. Black Pollarneff
15. New Kakyoin
16. Robber Soul 
17. Kan 
18. Pet Shop
19. Iced 
20. Jojo 
21. Dio
22. Shadow Dio

Change the difficulty to the easiest setting, and play Story Mode with anyone. Have the Super gauge at Max, and the Damage level at 4, perform your favorite characters powerful super (check command list for details, and there you go). You can play as either Jojo, S. Dio, or even Pet Shop (there are others too), since their stage count is 6, making the game finish quicker.

Here is a visual aid to getting most of the achievements in the game (with annotations), use it as reference on occasion.

JoJo's Bizarre Adventure (HD) Quick Achievement/Trophy Guide (Re-Updated) - YouTube