First of all, I must say that you should watch Clannad before Clannad After Story in order to fully appreciate Clannad After Story. I'm writing this review as a joint review of both.
Clannad, in my opinion, is best described as a PG-rated slice of high school life anime with a slow start. The first couple of episodes might be boring for a lot of people. Clannad has a bit of humor, and is a bit sad; it's a decent anime.
Clannad After Story on the other hand, I'm convinced was written and animated with the sole purpose of making you cry. Episodes 22-24 give the series a little bit of closure and remedy but also a bit of a bitter taste in my mouth to the effect that I kind of wish the anime had ended on episode 21.
Clannad After Story Episodes 1 through 21 are going to really push your buttons if you
1) had some major issues with your parent/ parents but have since reconciled or are considering reconciling
3) have a parent/ parents who made some major sacrifice for your sake when you were younger
2) was raised in a single household (by one parent)
3) have had a close family member die
If more than two of those apply to you or you've experienced more than one family death that you're not ready to fully confront yet I advise to NOT WATCH Clannad After Story. Or else have a therapist's number handy and a towel and maybe watch with a friend. I'm serious.
For everyone else, this anime will probably help you appreciate your family, your friends, and maybe even life a bit more.
Story: 7/10
There are holes, and After Story has huge chronological jumps. It felt a tad bit rushed at times. None of these contribute to the low score however. The one big thing that bothered me was the side story with the robot (no spoilers). I felt like that could have been so much better and more connections could have been made. I also found the ending a bit bullshit (episodes 22-24), but that's just personal preference. I will put in this disclaimer, that the anime is (and if it isn't it should be) tagged with supernatural, but the supernatural stuff comes off as a bit awkward as no clear rules or explanation of the supernatural are given and what happens (especially with Fuko) doesn't entirely make sense.
Art: 9/10
There is pretty much zero fan service. In fact this entire series is so PG you could almost mistake parents for virgins. That is but a side note however, and doesn't really factor into my rating. The choice of scenery and mood lighting in most scenes are very well done. This only misses a 10 because I want to emphasize how good the sound is. I particularly enjoyed seeing Nagisa's appearance mature.
Sound: 10/10
I was a bit annoyed by Nagisa's voice at first and for the first couple of episodes in Clannad quite a few of the female characters shared a similar tone of voice (will go over this more in Character section). However the overall use of sounds is great. I am especially impressed by the used of a musical motiff that is develops both in complexity and importance as we progress through the story (Dango Daikaizoku song). Though this is a semi-well known tactic, it is still very successful in creating a piece that not only lends itself to the story but embodies it. Dango Daikaizoku is one of those songs that will make you relive the anime every time you hear it.
Character: 7/10
It really bothered me how similar some of the characters were to the point that I got confused between them at the beginning. This might have affected my Art rating too but I felt like since it was confined to character drawing I would place the blame here. While there are some good character developments where needed and the two main characters are quite well developed, I felt like a greater diversity in character personality/ appearance/ tone of voice/ (love interest even) would have helped make both Clannad and Clannad After Story more interesting. For example, there was one point where I had difficulty telling Yusuke from Tomoya. Now this might have been an intentional plot point (no spoiler) but I still think it's an issue when there is any point in the anime where you can't differentiate the main character from a side character.
Enjoyment: 6/10
This is a bit of a tongue in cheek rating since I find it hard to rate something that made me cry like baby (mostly After Story) too high on the enjoyability scale. Most of the enjoyability part came from the slice of life stuff in Clannad and perhaps from the greater sense of appreciation for life and everyone/everything around me that I had after finishing After Story.
Overall: 10/10
As I was recommended this as a sad anime, I feel that I should appraise it as such. It is 10/10 one of the saddest animes out there. It may not be a perfect masterpiece, but if you're looking to cry this will probably do the job quite well.
