FIR presents a gripping storyline that maintains suspense throughout its runtime. The screenplay is tightly woven, with a focus on procedural elements that keep the audience engaged. The pacing is well-balanced, with the first half effectively setting up the mystery and characters, while the second half ramps up the tension and delivers impactful revelations.

The film's music, composed by Ashwath Naganathan, complements the narrative without overpowering it. The songs are situational and blend seamlessly into the story, while the background score enhances the thriller elements, adding to the overall mood and atmosphere. Cinematography by Arul Vincent captures the gritty and intense tone of the film effectively.

While the film excels in maintaining suspense, some viewers might find certain plot points predictable. However, the performances and technical aspects compensate well, making FIR a solid entry in the Tamil thriller genre.

Vishnu Vishal: Delivers a convincing and restrained performance as the determined police officer, effectively portraying the character's resolve and vulnerability.

Reba Monica John: Provides a strong supporting role with emotional depth, contributing significantly to the narrative.

Gautham Vasudev Menon: Offers a memorable cameo with his characteristic screen presence.