It's always difficult to judge a sequel on objective terms as the original always carries the edge of being "unprecedented" in a way or another.
Sure "The Mansion of Gods" wasn't a newcomer as the eight animated Asterix film but it was preceded by adaptations that belonged to the lesser category and movies that -despite their success- sowed incertitude over Asterix' adaptability in the minds of many fans... until Astier came.
And I loved his film because unlike its predecessors, it didn't try to emulate Disney or Pixar trends and that was the first credit I gave to the director and writer Alexandre Astier, a comedian who proved to be as much a fan of the little Gaul as Alain Chabat and a worthy successor. And it also helped that the film was a faithful adaptation of one of the best comic-book adventures, a sedentary one with an interesting commentary on deforestation, urbanism and its effect on environment, to put it simply an ecological and social view on the march of progress from the village's perspective.
While I was hoping a second Astier movie, I didn't know there was one in preparation so it caught me totally off guard. I came, I saw the trailer and then two fears conquered me.
First, the title "The Secret of the Magic Potion" gave the first major hint: it wasn't an adaptation, while this didn't prevent "The Twelve Tasks" to be a masterpiece, I was afraid Astier would get too carried away by the previous success and go a little overboard, making the kind of stories similar to the recent albums from Uderzo. Of course, one won't expect 100% realism for a series whose narrative is driven by a magic potion but it's pretty much handled like a McGuffin and only Uderzo is blamable for having gone as far as showing people getting bigger, turned into granite and worse, cows flying in the Atlantis or Alien invasion.
The second trouble was with the voices, for non-French speakers, Roger Carel is to Asterix what Mel Blanc was to many Looney Tunes characters, that he could voice the little Gaul during a time span of 47 years was a credit to his longevity and irreplaceability. But the lone survivor of a generation of voice-actors who shaped the childhoods of millions of children retired before the release, which prompted Astier to cast Christian Clavier. It wasn't the most unwise choice as Clavier is still the best live-action version of Asterix. I didn't have any problem with his voicing especially since Astérix isn't given a central role, the real focus is Getafix who must find a heir to transmit the secret of his most famous recipe, the magic potion that give a superhuman power to its drinker, except Obelix who "fell inside where he was little".
While indispensable in the series, the magic potion has catalyzed a few adventures such as "The Golden Sickle", "The Great Crossing" and "The Black Gold" which allows many fans to know a few ingredients, beside the mistletoe and the lobster (for the flavor) there must be some fish (reasonably fresh), some black oil, ultimately replaced by beetroot juice, for a better taste and the rest lies on Getafix' unique knowledge and can only be transmitted from druid's mouth to druid's ear.
The magic potion has always been a popular trope like the French equivalent of Popeye's spinach and the expression "to fall into something as a child" (meaning being good at it from the start) or "magic potion" (meaning a secret) has entered common language in French (like so many expressions coined by Goscinny). So the initial idea was good, though the fact that it was a broken ankle that pushed Getafix to contemplate his decline was rather far-fetched. Didn't he fall after saving a bird and making stunts that could have made Disney's Tarzan yodel with jealousy? He did act like a prima-donna that was so unlike his usual venerability.
Anyway, what Getafix wants, Getafix gets. So he is escorted by Asterix and Obelix to the quest for the right successor, he sends a small herd of boars to call his 'fellow druids' for a special meeting at the Carnutes forest. And the druids part restored my confidence in Astier's humor, except for one tiny detail, not so tiny but the size of a child actually.
The first film had a cute relationship between Obelix and a Roman child, one that wasn't overplayed and didn't make an underdog hero out of the child. Of course, once the little girl pops up in a school scene, my intuition anticipated everything and accurately so, I was afraid it would another of these Moana-Frozen "chosen one" things again. First of all, she doesn't belong to the film's canon. Not that it matters but who are their parents anyway? Aren't they worried over her disappearance? It doesn't take an Asterix fan to understand what she was doing, only being aware of most family-friendly movies trends. I suspect some marketing behind that choice, it didn't have the Astier zest in it.
Overall, the film provides a nice backstory of Getafix and an interesting rival in Sulfurix, the druid who's clearly more powerful and whose only flaw is not to have invented the magic potion, his alliance with the Romans and the fact that the Gauls left the village to pick before the journey, made the climax rather predictable but I guess it was spectacular enough to make for a positive impact, maybe because there's always that self-awareness in Astier that has a certain ring to it.
So I liked it in the sense that it stayed faithful to the first film's spirit and didn't take any major deviation, I only wish it could have deviated more for some stuff we've seen in so many animated movies, especially coming from Astier...ix.