Writer-director Siddique seems to be completely ignorant about the (positive) changes that Malayalam cinema has undergone in the last decade. His solo outings have all been dreadful (yes, including Hitler, Chronic Bachelor, and everything else); Big Brother is probably the worst film he has made thus far. Siddique, someone who's known for his light comedies, ventures into the pure action genre yielding disastrous results.
The screenplay throws a couple of interesting curveballs at the viewer in the beginning. A prisoner who has been out-of-touch with the modern world for more than two decades (re)adjusting to his family surroundings is actually not such a boring concept, to begin with. If the treatment had been decent, we could have still had a not-bad entertainer in our hands. But with Siddique's intention purely to package Mohanlal as some initially-subdued-but-way-larger-than-life dude (with even night-vision capabilities) named Sachidanandan, the film heads nowhere.
The supporting cast doesn't have much to do. Sarjano Khalid overacts on a lot of occasions, Anoop Menon is barely there, and Arbaaz Khan's lipsync is way off (looks like he was mouthing his lines in Hindi itself with actor Vineeth's voice dubbed over his, during re-recording). The trio of cronies (played by Irshad, Tini Tom, and Vishnu Unnikrishnan) is also okay at best. This time around, the comedy quotient is far too less (even for Siddique's standards) and more emphasis is given to the numerous uninteresting set-pieces.
The key female characters (if you can call them that) also don't have anything substantial to do. The way the movie explains the Stockholm Syndrome was downright laughable. Deepak Dev comes up with a set of forgettable songs and moody background score (the same guy did impressive work in 'Lucifer' just to recall). With a hotchpotch of a screenplay and a butt-numbing run-time of 165 minutes, Big Brother proves to be a complete snoozefest.
