The movie is great. I watched the movie without watching the trailer and I really liked the pace and slow unravellling of the plot of the movie.
The change in emotion is shown very subtly in a movie like in a song or just with a music and expression .
I feel the trailer gives away few things so if you have watched the trailer you may not like the movie that much.
When I started watching the movie I was only aware of a person who is staying at house for a period of time and all the questions that came in the protagonist (nephew of the person) was similar to the question coming in viewer mind and it was like each layer is peeled so slowly and swiftly that you just love and live each of the beautiful moments.
PS. I am a non Bengali viewer and have seen that many people like to give high rating because of love for their movies dialect or region and when you watch it you think the movie is overrated but this rating is not because of any bias or pre-notion.