They should've taken more time in the first episodes, the amount of information they were giving us was overwhelming and it felt like they were throwing it all at your face just so the story could proceed to the actual arc they focused this season, whereas when we reach around half of the anime they take a lot of time... Don't get me wrong, it's not a bad thing but in my opinion, they could've balanced with the beginning.
Also with the first season, the anime took their time to build relationships and show the charisma of the characters, how despite them being kids (a lot of them were in the first season), they had dreams, convictions and virtues very well written from a "young mind" point of view - they were all good kids, with unfortunate life but huge heart.
The characters this season doesn't make you feel empathetic towards them - they don't share the same charisma the characters from the first season did, a lot of new characters presented and vanished without showing personality and much impact.
And that can be explained because apart from 1 character, none of them was actually shown overcoming hardships with MC, so you couldn't "feel" the friendship or brotherhood like the ones in the first season.
They didn't do a good job with world building too, in the first season you could feel what age they were according to their interaction with the scenery, technology and their related cultures for the time.
And lastly, the animation was just good... not as great as the first season which had some great attention to little details. For example when Parona was climbing the wall, she would feel the cracks to see if she could hold before putting the hands.
