Mari Okada as a director and studio P.A. Works were able to unleash their full potential with "Maquia : when the promised flower blooms"

I've actually seen a lot of bad reviews for it, probable reasons are :

-Early subs for the movie (pre blu-ray releases fansubs) are really messy : sentences are badly turned, which makes some scenes lose sense(like the one between Maquia and Krim). Moreover there are a lot of timeskips thus the viewer needs full attention to get into the flow of the movie.

-Some people just hate Mari Okada or don't connect with her works. She has a unique style of storytelling and pacing that is different from what you usually see in anime productions.

-Lastly you need a certain emotional maturity to fully grasp Maquia and Ariel motivations.
Thus I wouldn't recommend the movie to teens. The reason being that teenagers generally lack the required retrospective on their own lives to understand and feel empathy towards the mother and child relationship that Maquia and Ariel have.

Each of us have at some point acted cold towards our mothers and then reconciliated with them towards early adulthood, and that is the accuracy in the interactions between Maquia and Ariel that makes it such a good movie. I was laughing when Maquia and Ariel were laughing, I was crying when they were crying and I was cringing when Ariel was doing something stupid because I have also been there before.The way they interacted felt so real to me because I can look back and relate to most of their situations.

The art was gorgeous especially background art and the character designer Akihiko Yoshida (Nier Automata, Final fantasy tactics) models blend in well with it.

Another highlight is the sound : voice actors for Maquia, Leila and both V.A. for Ariel ( child and adult) made a poignant performance.
The ost is also really pleasant to the ears and is timed well with the strong moments from the movie making them even stronger. You could however nitpick about the lack of variety in it.

In conclusion: Maquia is a tale about motherhood and the shapes it can take and it capitalises on the empathy one will feel towards its characters. However once it grips you, you're in for a roller coaster of emotions confirming Okada's "genius of character drama" title.