Some movies are made unique, some movies have unique script, some unique actors. This one is based on such a unique and gruesome narration that was brushed under carpet for decades that it really dint need any other thing. But the strong acting by Anupam Kher, Pallavi Joshi and a superior screenplay are just a cherry on top.
You will hear all the reviews about the movie that its a propaganda, creates hatred and all. Just remember, Nazis were never happy when movies like Schindler's list were made and they would have also termed the movie as false/ creating hatred.
Nobody likes their dark side to get exposed. So I can only suggest, before watching the movie; read about the incident, see independent interviews if any (there are very few on it) and then watch the movie so you see it unbiased. And then decide for yourself what is truth.
But for me, Vivek Agnihotri, I take a bow to you sir. It needs more than guts to make movie on such a topic.