Any film that respects its audience is considered as a good movie. The debutante director of Sathru has done a good job in that aspect. It's a simple cat and mouse police game, but with a number of well written (not well staged) interesting twists. The director did a very good job by making the movie almost without any logical loopholes. Though there was a scene of coincidence, the plot development manages to justify it. Again, its because the director respects the audience.
The places where the movie struggles are dubbing,screenplay and the climax. I think the director wanted the movie to be under 2 hours, that's why the climax felt rushed up. I would've happily traded an extra 20 minutes for a more interesting climax , which I think the director is very capable of.
With slightly more budget, better screenplay, and better climax, this movie could've been a first class thriller like Thani Oruvan. But nonetheless, all this can be neglected, given that it's the director's first movie.