The parts involving the matches and cricketers in general were great. Especially, the bowling action of Kapil Dev, Marshall and Madan Lal. The fact that the late Malcolm Marshall was played by his real life son was astonishing. They nailed the Ravi Shastri celebration, the Sunil Gavaskar stance, Viv Richards' mannerisms and that iconic catch from Kapil.
The problems I have with the film are the unnecessary angle of riots and that ridiculous part where Pak army decides to not fire to let Indian army losten to the finals on radio. That was not at all required and is totally unbelievable. They even showed some shots where the Indian soldiers were listening the radio while the fires and bombings were happening around. A real soldier in any army in the world will never do such a thing. These parts of the film felt like director's personal propaganda being pushed.
Overall, I am giving it 3 stars for the cricket-related parts and the efforts they took on bowling actions, stance and mannerisms of the cricketers.