This anime adapts the first 19 chapters of a manga that spans 12 volumes and 63 chapters total. And of course, it had to leave out a fair bit to make it even that far.
The art work and the voice acting make this a very special anime. The art in the manga was great, but after watching the anime, I feel like the manga was a bit minimalist. The extra detail, and of course the color, make the anime a really special experience. And the voice actors were incredible. Every single VA was perfect. It was as if I had known the characters and their voices for years. Every actor recreated their character perfectly, and never have I heard such believable child characters.
However, I strongly recommend reading the manga first. The original story includes some flashbacks, some travel episodes, and several epilogues or postscripts to wrap up important subplots. The story is obviously very incomplete at the end of the anime. It might be possible to make it all the way through the next 12 years of the story if it gets another season. But the only way to get the whole story is going to be reading the manga. And it is well worth it!
Finally, this show is a great educational program for basic Japanese cooking. I'm in the process of collecting all the manga just to have the recipes that are included.
Sweetness and Lightning is a true slice of life and Iyashikei experience. Negative reviews are from viewers who had unrealistic expectations or were expecting something other than slice of life. Sweetness and Lightning is truly a masterpiece, although as an anime it remains incomplete.