It's not bad, but there are a couple things that could be improved:
DIO's timestop appears to be glitched, but only on the player's side. When I use it, all I can do is move around and perform a single hit on the enemy. I can't charge up my stand, I can't use any stand attacks (i.e stand barrage or knife throw) or anything else. Doing a single hit on the enemy also automatically stops timestop. Enemy DIO timestop can let him use his stand barrage/stand attacks though, so it's unfair on the player.
A.I Jotaro constantly abuses his counter move, even on easy mode. Whenever I attack him it's usually a 1/3 chance that I'll get countered, which seems way too much to be fair, considering how strong the move is.
Whenever I use a stand barrage with Jotaro/DIO it can just randomly stop after the first or second punch or be interrupted by the enemy, but this never happens when the enemy uses their stand barrage.
If these are fixed then this could be a pretty decent game, but otherwise it's kind of frustrating.