*Minor spoilers ahead*
How does one continue a story that has already wrapped up perfectly? The announcement of a Steins;Gate sequel film was inevitably met by both caution and anticipation. Like the concept of travelling backwards in time, Steins;Gate: Fuka Ryouiki no Déjà vu is a paradox. It does not need to exist, and yet it still has every right to.
It could have been an ordinary piece of fanservice, a throwaway story, and some would have been perfectly content with that. It could have been a forgettable prequel or even a retelling of the TV series' story. There were so many options available that you can't help but wonder, why on Earth did they choose to make a direct sequel of all things? It's almost as if they were asking, begging for a disaster.
The end result has proven to be anything but a disaster. This is a continuation every bit as compelling as it is justified.
Taking place exactly one year after the events of the main series, Fuka Ryouiki no Déjà vu depicts a seemingly blissful world. There is no SERN, no time machines, no unavoidable deaths-- but still something is amiss. Okabe's memories are distorted. His experiences with time travel have made him an unstable entity. Perhaps it's just a fit of emotional trauma, he thinks, but his worst fears are realised when he suddenly disappears from existence, trapped between multiple World Lines. Miraculously, Kurisu manages to remember Okabe's existence through a steady case of deja vu - determined now to do everything she can to stop him from disappearing forever.
Kurisu's role as the protagonist is the film's greatest strength. While the TV series primarily focused on her intellect and relationship with Okabe, the film instead decides to show a more human side to her character. Kurisu's emotional state takes the centre stage this time, her being subjected to many of the same horrors that Okabe previously experienced. Even when it comes to the light-hearted 'moe' scenes (and there's quite a few in the beginning), Kurisu's personality remains consistent and believable. She acts flustered and embarrassed not for cheap pandering, but because she's not used to having close relationships - she's dedicated her entire life to science. The term "tsundere" does not even feel appropriate. Kurisu is simply a human being with her own flawed personality... although, to be fair, she is pretty much the modern day Einstein.
Fans of Okabe will not be disappointed either. There is plenty of the usual banter and Hououin Kyouma shenanigans within the first thirty minutes of the story. It's only after that point that Okabe actually begins to disappear, and the minutes after still occasionally see him appear. What makes Okabe stand out, however, are the moments between him and Kurisu. We see the romance explored in much greater detail than the TV series, which more or less ended it at a single kiss scene. One of the most powerful moments in the entire series (not something to be said lightly) occurs as Okabe painfully convinces Kurisu to forget him, content with disappearing in return for her safety. Without an episode number to constantly remind us that there's more story to come, there is a perpetual feeling of anxiety not knowing what might happen. What if it actually ends that way? Nothing is for certain.
Also of note is a short scene near the beginning with a drunk Kurisu teasing Okabe and rubbing against his face. I may just nominate that for the cutest moment of the year.
The rest of the cast is largely ignored, but it is mostly for the better. The side characters have never been the series' strong suit, particularly with regards to Mayuri, so scatterbrained that you would assume she has brain damage. The @channel references are also kept to a minimum this time around, although there is still plenty of the ol' Dr. Pepper advertising.
For as great as Kurisu's and Okabe's characterisation is, there are still some minor faults in the story. My main gripe is that there is a lot of build-up and yet very little climax. The entire story builds up towards something grand... and then it all ends within about five minutes of talking on a bench. Compared to the last two episodes of the main series, it all feels a bit disappointing. Perhaps it simply needed an extra ten or twenty minutes of screen-time, as the rest of the film never felt like it was being rushed. There is also a short instance of melodrama (Kurisu running and falling as she chases after Okabe) and the changes made to the sci-fi canon would have benefited from a stronger explanation, but neither of these are bothersome enough to dampen the overall experience. Just don't be expecting much realism from the science aspect - this is a story about time travel, after all.
Much like the TV series, the soundtrack of Fuka Ryouiki no Déjà vu is stellar all-around. The score mainly comprises of ambient sound and moody piano pieces, subtle enough to add to the atmosphere without being overbearing. In the one scene where the music is most noticeable (a piano version of the main theme playing in the background), it is genuinely emotional, never melodramatic. Kanako Ito also makes a return for the opening song of the film, effectively creating a sense of familiarity for fans of the series. Special props should also be given to Asami Imai for providing some of the strongest voice acting in years.
The visual quality is about on par with the TV series. While there is little animation and few scenes that strike the eye, it never quite feels like it needed more than that. It is consistent and plenty adequate for an animated film. My only complaint is that it lacks colour - the original Huke artwork from the visual novel was so much more interesting.
Steins;Gate: Fuka Ryouiki no Déjà vu is a veritable triumph. Rather than simply exist as a superfluous sequel (or worse - a bad one), it succeeds in enhancing the overall story. Kurisu is now as strong of a character as Okabe ever was. The relationship between the two has finally been explored with the attention and detail that it truly deserves. This is the definitive end to the story and it proves difficult to let go. Maybe it didn't need to exist, but I'm still glad it was made. Some things are worth waiting for.