Performance (especially Kangana, though the supporting cast is exceptional too), costumes, score, cinematography - everything in the film works very well. Editing could have been better - in many places, the events feel disjointed, though admittedly, because the screenplay had to jump places, I cannot imagine what could have been done to make it more easy-flowing. Kangana;'s performance goes a full arc from an innocent but brave teenager, a wife and lover, a mother and to finally a patriotic warrior, and she nails every shade with priceless facial expressions.
To be clear, if you are expecting a multilayered biopic that explores the Rani's character in depth, this movie is not that and it is very obvious that the film-makers did not have that goal in mind. The Rani is therefore depicted somewhat like a real-life superwoman from the annals of history, and just like 'Gandhi' did for Karamchand Gandhi, everything in the film, including the supporting cast, has the sole purpose of polishing that image of Rani Laxmibai's as a virtuous warrior and a superwoman. I think it is very important for the audience to understand what expectations to go into the theater with.
Having said that, it should be mentioned that the audience will be treated to a pretty well-depicted backstory of the Rani's life in the first half - before she became the "veerangana" who fought the British. It would not be incorrect to say that if you love emotional drama, the first is your half of the movie and if you love action, the second is your half.
To conclude, you are in for a huge treat if you are Kangana's fan and if you have loved movies like 'Braveheart', 'Gladiator' and '300' - this movie glorifies the Rani's saga in pretty much the same manner that '300' glorified that of the Spartans.