The animation changes totally, I couldnt find an explanation to it, but thats not the worst thing, they also reanimated the flashbacks and changed things along the way. So be prepair to relive the story because half of the episodes has this flashbacks that we already have seen but with some changes.
The story keeps moving foward but very slow, its tedious how they keep going backward with the flashbacks, since the episodes are really short you have half main story going and the other half it's the "context".
I wished I knew this from the start so I stopped watching when the old animation ended or just started in this one, I can't understand why they consider this a prequel.
So in conclusion its good, but if you are watching this season as it would have started here and not two seasons ago.