It's a sequel to Memories, or a prequel, depending.
Story-
Half of this story takes place in the past, which helps explain things from the first season that made everyone say "Wait, what was that?!". You see a semi-new story, well a side story really, but it's still nice.
Art-
Carries the same style from the first season. It's still nice.
Sound-
Where this anime really shines. The OP and ED are just awesome. In show music is very mood-setting. It's both relevant and well-done.
Character-
He's an ass! (You know who) Aside from that, most of the other 3 characters are likeable, although Mizuki is super-needy, it fits her char. well.
Enjoyment-
You may or may not enjoy this as much as the first season. It's iffy. I really only watched it because of the first season, and it didn't add too much. It's also a breeding ground for melodrama.
Overall-
If you liked Memories, watch melodies.
