The film is quite impressive when compared to Sandip Ray's previous films. Simply put it's a good story told to a tee. The positive factors are the tight script, well supported background music, and the nice use of camera in giving us a taste of Nawabi Lucknow.
Yes, the film could have been better. There are certain aspects which could have made a difference like the acting prowess of Soumitra Chatterjee to bring alive the character, intelligent and tighter script for which Satyajit Ray was well known, and lastly the presence of Jatayu to add another dimension (though we do not have Jatayu in the story of Badshahi Angti). These aspects together could have provided a much tighter integration with the concept of Feluda that is so well ingrained in the minds of middle-class Bengali. But shortcomings are simply beyond the control of the present director.
So it is not fair to always fall back on earlier films of Satyajit Ray, and come out with a criticism. On the contrary we should praise the fact that in spite of all the inherent shortcomings Sandip Ray has managed to come with a smart and absorbing Feluda film. So, watch the film as it is without carrying the past movies in mind. Thanks to Sandip Ray and his whole film unit in making this Feluda film a success.