POTENTIAL SPOILERS! If you haven't watch any of the Steins; Gate nor seen the movie, please read at your own discretion. There may be spoilers, you've been warned!
Synopsis -One year after the events of Steins; Gate, with Kurisu Makise coming home to Japan for a lecture. During the visit, Okabe Rintaro has been suffering the side effects of his action more frequently and longer, which he ultimately disappears in front of Kurisu. Yes, that visit to America episode does count.
Story - The story primary follows Kurisu Makise, her feelings for Okabe Rintaro and her struggle to save Okabe which contrast the anime, which followed Okabe, his feelings and his struggles to save Kurisu. And throughout the movie, it shows the importance of Okabe while connecting Kurisu's feeling for Okabe together. The movie is definitely an epilogue to the anime, so if you're looking for closure or more from the series, then it's a must watch.
The quality of the story holds true to Steins; Gate but do not expect a rollercoaster of twists, and turns for the plot. However, while the plot might not leave your head in pain, it does leave a whole lot of feel!!!
Too many feels to be held.
Characters - All the main cast makes their return in one form or another. However, unlike the anime, they serve more to help Kurisu understand how important Okabe is in their lives even if no one can remember him. Also, it really highlights Kurisu's character flaw in this movie. She's a genius but ultimately her pride gets in the way of accomplishing the things Okabe would have done in a heartbeat.
And the voice acting is wonderful (even if it's really just Kurisu doing most of the talking). =3 Kurisu!!!!!
Overall, it's a well pace story. It didn't feel too fast or too slow and allows you to really understand Kurisu's feeling (not all were shown but explained, because time travel). If you're expecting a lot of action, don't. It's all about the feel with this movie.