I had not realized this was a sequel until I was done watching. This may have affected my experience, but I don't think so. This movie still works as a stand-alone movie.
I loved everything about this movie. I love the story, the acting, the actors' chemistry, and the message it sends. I think the director/producer or whoever, made every second of this movie important to the arc of the plot. The only issue I had overall was that I did not like the ending. Although I understand why custody was given to the mother and the reasoning behind that decision, a small part of me wished Nagisa had custody especially since Sora seemed so happy with him. Also, I loved the way Nagisa and Shun's relationship progressed (even though I don't know the context of their fight or their dynamic) I was bursting with pride when Shun became comfortable with himself when he came out. Overall good message, a good story, and a great movie! I will watch the first one and then rewatch this.