The gif is from the show's opening sequence, and is slightly smoother than the actual animation (which is typical of most modern cartoon intros). Not sure if you're apart of the youtube boycott until the 13th, but here's the opening sequence:
Spoiler's below for season 1
The writing and animation quality is great. The visuals are breath taking at times, especially when mythical creatures are involved like the Tide Mice scenes and the Mara (witches that feed off and cause nightmares). The world is enchanting as Hilda and her mom live in a cabin in the woods.
After a couple of episodes they are forced to move to the city of Trolberg. Hilda, who liked being out in the wilderness, is not a fan of moving to the city and is trying to acclimate to the "boring" life of a city dweller. She then encounters more mythical beings in the city, which was a surprise to her, seeing that she thought they only lived in the wilderness (one of the reasons why she wanted to stay in the forest).
She makes a couple of friends and goes on adventures. As sitnspin said, its episodic but it builds upon itself and maintains continuity throughout. It was interesting re-watching it a second time and noticing how they tease future stories, creatures, and characters that may not show up for several episodes. So there is a bit of re-watchability to the first season. I don't know if its because of the art style or the setting, but I get some Ikea vibes at times. This makes sense since this is a Scandinavian (possibly Norwegian) setting. Its a chill time and something to watch when you want to unwind.
My favorite episode of season 1:
Is when Hilda goes to the Library and stumbles on the arcane book section which was hidden behind a secret passage. She finds a book of spells that the Librarian cautions her on using. She photo copies a spell she thinks may help her friend that is having a string of bad luck. After photo copying the section, she performs the spell. It seems to be working for the friend, so she does it for her mom that's also having some bad luck. Things are going great for them... until this starts happening at random intervals to her mom and friend:
(https://media0.giphy.com/media/2fSfCfWeYdQbySWeh9/giphy.gif)
With some help of her elf friend, Alfur, and another friend, they figured out that she didn't read the spell in it entirety; having missing some important footnotes not on the page she copied, they have a limited time to save her mom and friend before Hilda absorbs their souls.
And here is season 2's trailer: