After having done a rewatch of the entire series, I delved into the eggs and movies for the first time and I must say that this particular movie far exceeded my expectations of what an anime movie should be. What's more, the attention to detail, the animation and the landscapes at times make you think that you are watching a Studio Ghibli film (obviously without their artistic style). The plot of the movie is simple but it gives a lot of context to the lore related to Goudy, the animation of the spells is simply great, the fights are very fluid and you can reallyconnect with Rina as a character, in the sense of why she makes the decision to fight the bad guys and bet on great spells when the situation overwhelms her.

I give it a 9 in relation to the score I gave to the main plot, with Slayer Next being the only one to reach that score.
I totally recommend it but not to start with the franchise, I would leave the bar very high in terms of animation.