I'll write a quick review for the prequel film of the series 'Sayonara Watashi no Cramer'. Yes, if you are planning to watch the show you should watch this movie first. The show references the movie a handful of times and it's important to understanding Onda as a character.
Story: Fairly good story that's straightforward. It follows Nozomi Onda who loves football (soccer) but now finds herself being told by everyone that her frame is too small to be playing with boys. You follow her journey of frustration and struggles, being looked down upon simply by being a girl. The writing is good but not special, and doesn't get anything horrendously wrong. 7/10.
Art: It's better looking than the show especially in a few moments. The show utilizes some 'tricks' to not display as much footage of actual football being played however the film instead opts to use CGI for a decent amount of the duration of the match. Personally I think the CGI looks ok. There was no bad 2d animation from what I remember, it was noticeably consistent. Nothing groundbreaking but it looks good for the most part. 7/10.
Sound: There's some good insert songs and I enjoyed the score quite a lot. 7/10.
Character: It's very Onda focused and the film suffers a bit because of that. However I did enjoy seeing the relationship of Onda and her friend Sawa Echizen. Lacks the charm the characters in the show provide but still not horrible. 5/10.
Enjoyment: It felt like a film and not just episodes stitched together. I was confused at times in the show because I didn't really understand why Onda was the way she was. Thankfully the movie does provide context. I enjoyed how it was structured and there was a lot of actual football being played. Fun to watch. 7/10.
Side note about the romance tag: There's maybe 2 or 3 short scenes where romance is hinted/talked about but it's not a center of importance. Nothing comes of it and (so far) has been irrelevant to the show.