Overall
Yeah, that's what I thought; the first Clannad season had to get a real ending. "After story" picks up right where the prequel left off, but after a couple of episodes it really changes theme as the characters grow up. There are a lot of twists and I wasn't sure what to think of it all, the story felt pretty pointless. Until the last episode, that is. Rarely have I seen an anime (or rather two in this case) been saved by its last episode in such a huge fashion.
Beautiful stuff!
Animation
The animation is about the same as in the first season; perhaps a bit worse than that.
Sound
Voice talents are great, music not so much. But after over 40 episodes, the Dango song actually sticks.
Story
Well, it starts off as a high school comedy but soon turns into a really emotional drama. Deep stuff, but I really wandered what the heck the point of the story was after a while. And it all gets explained in the end in a very beautiful way.
Character
The lion part of "after story" focusses on just a few characters, and it's a bit of a shame the ones from school don't get more attention after getting so much background in the first season. In the end, it wasn't a big deal, but it probably would have been even better with a bit of a wider focus.
The characters that do get screen time mostly get just that; screen time. There isn't a whole lot of interesting development, just story.
Value
Definitely worth watching several times, together with the first season.