Admirable, but not enjoyable
This film didn't generate much buzz when it was announced. Although the book by Sanjaya Baru did. The trailer did generate a sort of controversy, which might have added to the buzz.

Plotline & Screenplay:
This film takes on the life of dr. Manmohan Singh, who served as the Prime Minister of India from 2004 to 2014, and the internal politics to which he fell prey of.
The trailer made the story very clear. It was just that the people were excited to watch the inside of PMO.
The screenplay was good, but it lacked taste. It made the film serious. The film was more of a documentry, presented through the eyes of Sanjaya baru, who served as the Media Advisor to the PM. Though there was some humour between the film, but i'm pretty sure that those who favour masala will surely dislike this film.

Anupam Kher lives his character throughout the film. He is just the right Dr. Manmohan Singh. You'll always feel that he is not Anupam Kher. You'll never realise that. His voice modulation, his walking style, his expressions, are all just the same.
Akshaye Khanna did a great job. We all know how fine an actor he is, and he never fails to prove that. He also broke the fourth wall and talked to the audiences in between.

Direction & Music:
Debutant Vijay Ratnakar Gutte did a great job. His direction was really good. He never made the film deflect from the track.
Talking about the music, there are no songs in the film. But the background music keeps you glued to the screen.

If you are a drama admirer, go atch this film. You'll surely love it.
Anupam Kher caricatures Manmohan Singh in hit job on Congress in the official trailer for The Accidental Prime Minister #trailer
The Accidental Prime Minister | Official Trailer | Releasing January 11 2019