I firstly heard of the original movie the day Shaitaan's trailer was released, and seeing how well Vash was received, and this being a remake, I didn't really get my hopes up but still the trailer got me hooked, so I went.
Needless to say, I came out surprised. The movie had some really thrilling sequences and the overall ambience was really well catered to the theme of the movie. All actors gave a tremedous performance, along with the music amplifying the gravity of these odd affairs.
Now, I would admit that this movie did have some slight issues like some questionable and possibly, dumb choices that the protagonists made (which I can't disclose here), and some 'moral of the story' like dialogues and a few villainous ones which I don't really mind but here they just felt forced.
Apart from all these, it's a real good thriller, and especially Madhavan's performance, steals the show. The viewer is captivated throughout the length of the film because of the intense scenes and always expecting the unexpected. Overall, this is definitely worth the time.