Ramesh Selvan’s film could have been quite enjoyable if he'd managed to cast a more suitable actor in the lead role. However, the title isn't simply Thalaivan; it's Bas In Thalaivan, which means we are stuck watching this self-indulgent introduction of a newcomer who has noticeable cheek and jowl features, constantly bloodshot eyes, and a protruding belly. These physical attributes might have been overlooked if he showed any acting ability at all, but unfortunately, his performance consists of just one unchanging expression, regardless of whether the scene is romantic, emotional, or intended to be humorous. To give credit where it’s due, the female lead also seems detached; her lip synchronization suggests she could easily be reciting Latin! If you can manage to overlook the actors in the main roles, the film goes from being nearly unwatchable to just barely acceptable. The narrative centers on a terrorist named Daniel, who was involved in planning the 2008 Mumbai attacks. Anwar Khan, his former mentor and rival whom he couldn't eliminate during an attempted takeover, makes an agreement with the police, leading to Danny’s associates being killed in staged encounters. Even as the Director General of Police Sundarapandian claims to be making the city safe, a mysterious figure—the Thalaivan mentioned in the title—begins committing crimes right under the law enforcement's noses. The question is: who is this person and what does he ultimately want? The story itself has potential for a commercial film, and Ramesh Selvan seems to understand how to maintain its momentum. There are betrayals, an inventive strategy (to capture Thalaivan), some welcome brief appearances (from Kota Srinivasa Rao and Power Star Srinivasan), a reasonably acceptable flashback sequence with Jayaprakash, and a somewhat amusing comedy segment featuring Santhanam. However, the plot developments are predictable well in advance, so there’s no real suspense during those moments. For example, when Bas is reluctant to discuss his parents, you know a tragic backstory is coming. Similarly, when police officers are put on hold, it's obvious they're corrupt and, as expected, we see them conspiring with Danny. This lack of subtlety makes the overall presentation feel careless and uninspired.

Source on TMDB