Whenever it works well, “Rogue One: A Star Wars Story” feels like the best Star Wars movie since the original Star Wars trilogy. Although it is riddled with several weak spots in terms of plot and characters especially during its first half, the movie eventually becomes more exciting as efficiently and spectacularly culminating to its expected finale. Overall, it does more than it is required to do as a spin-off product placed between “Star Wars: Revenge of the Sith” (2005) and “Star Wars: A New Hope” (1977).

Expanded from what was briefly mentioned in “Star Wars: A New Hope”, its story is mainly driven by what may completely change the course of the ongoing war between the Empire and the Rebel Alliance. As the Empire completes the construction of the Death Star, Galen Erso (Mads Mikkelsen), a scientist who was forced to help the design and construction of this infamous superweapon of mass destruction after being separated from his dear family, covertly sends his old friend Saw Gerrera (Forest Whitaker) an important message via a defecting Imperial cargo pilot, but the circumstance is not that good at all. The leaders of the Rebel Alliances are certainly interested in that message, but Saw is not so friendly to them as the rogue leader of an extremist faction fighting against the Imperial Military in a desert planet called Jedha, so they need someone who can approach to Saw without any suspicion or hostility from him.

That is how Jyn Erso (Felicity Jones), Galen’s daughter who has lived a criminal life alone since she grew up under Saw’s protection, comes into the picture. When she is being transported to a labor camp, she is rescued by Rebel Alliance intelligence officer Cassian Andor (Diego Luna), and she agrees to help the Rebel Alliance mainly because they promise a reward she cannot refuse.

She and Cassian soon go to Jedha for finding and meeting Saw, and the movie gradually assembles several supporting characters around them. They are K-2SO (voiced by Alan Tudyk), a re-programmed Imperial enforcer droid who is pretty much like a calmer version of C-3PO; Chirrut Îmwe (Donnie Yen), a blind but skillful warrior who believes in the Force as he frequently emphasizes to himself and others; Baze Malbus (Jiang Wen), Chirrut’s friend who can do a lot more than being around Chirrut; and Bodhi Rook (Riz Ahmed), the aforementioned Imperial cargo pilot who finds himself facing far more risk than expected as getting involved with Jyn and Cassian.

On the opposite side, we meet one new villain character besides two familiar old ones. As a high-ranking Imperial Military officer who has supervised the construction of the Death Star and is also directly responsible for Galen and Jyn’s miseries, Ben Mendelsohn is suitably despicable, and his best moment comes from when his character feels frustrated about not being rewarded enough to satisfy his lifelong ambition. Voiced by James Earl Jones as usual, Darth Vader shows more of his fearsome side, and Grand Moff Tarkin, who was played by late Peter Cushing in “Star Wars: A New Hope”, is chilly and heartless, which is no surprise considering that he is presented here via the CGI based on Cushing’s performance.

While introducing all these characters, its first half often stumbles because of its bumpy plot progress and rather weak characterization, but then the movie comes to gain narrative momentum as everything is set for action. The action sequences in the film are notably grittier and tougher than the ones in other Star Wars movies, and the sense of real danger is palpable as Jyn and other characters around her struggle through a series of perilous moments which may get them killed at any point. Looking more competent and threatening than ever here in this film, Stormtroopers shoot better than usual, and the Death Star has a grand, terrifying scene to behold when its destructive power is tested for the first time.

The movie is directed by Gareth Edwards, who previously directed “Monsters” (2010) and “Godzilla” (2014). While quite different from each other, both “Monsters” and “Godzilla” showed that Edwards is a filmmaker who really knows how to use special effects well for dramatic purposes, and “Rogue One: A Star Wars Story” further confirms his mastery of special effects especially during its climax sequence, which is the best CGI action sequence I have ever seen during this year. Yes, I have recently complained about how much I feel exhausted and bored with those big, massive CGI spectacles in numerous blockbuster films, but this actually engaged me right from the beginning and then thrilled me to the end with considerable satisfaction. While it busily shuffles between different places and characters, we never get confused amidst lots of bangs and crashes, and we come to care more about how the story inevitably comes to its ending.

It is a little shame that Jyn and her comrades are not as distinctive as Rey or Finn in “Star Wars: The Force Awakens” (2015), but they function well together as a group we can root for at least. While Felicity Jones and Diego Luna have more things to play as their characters come to trust and depend on each other along the plot, Riz Ahmed, Donnie Yen, and Jiang Wen fill their respective archetype supporting roles as demanded, and Alan Tudyk has a juicy fun with the deadpan attitude of his robot character.

While it is not without flaws, “Rogue One: A Star Wars Story” did a good job in many aspects. While feeling darker than other Star Wars movies in comparison, the movie also stays true to the mood and spirit of the original Star Wars trilogy, and that is further accentuated by Michael Giacchino’s score, which is appropriately based on John Williams’ music from the original Star Wars trilogy. The Force is strong in this movie, and that is more than enough for me to have some expectation on whatever will come next.

Sidenote: I watched the movie not long after hearing the news of Carrie Fisher’s death, and her brief appearance during the last scene felt quite poignant to me. Rest in peace, Miss Fisher.