The initial stretch of director Rohin Venkatesan's Petromax appears to be a typical horror film, where Meera (played by Tamannaah) and her family are at the receiving end of some jump scares. The scene subverts the climactic twist of 'The Sixth Sense', as the ones who usually frighten were those who became prey to them. But despite having good ideas on paper, the middling execution misses to translate it on screen. Petromax is produced by A. Kumar under the banner Eagle's Eye Productions.

Adapted from the 2017 Telugu film 'Anando Brahmma', the story of Petromax revolves around a spooky bungalow that is haunted by the spirits of Meera (played by Tamannaah) and her foster family of three (played by KSG Venkatesh, baby Monekha and 'Pei' Krishnan). As they prove to be the biggest obstacle for proprietor Saravanan (Prem) to sell the property, he hires four desperate strangers - Senthil (Munishkanth Ramadoss), Thangam (Kaali Venkat), a deaf watchman Nandha (Sathyan) and Kaali (TSK) to dispel the myths surrounding the house by staying there for four nights.

Petromax makes a lesser impact as a horror film, due to the predictability surrounded by it. But the lack of invention in that realm works well, as the narrative manages to turn the cliches and the tropes over its head through a hilarious stretch in the second half. Even the quirks of Senthil's motley crew are introduced beforehand through a funny, yet overstretched backstories that unfold in a hospital. But the screenplay over-uses this technique, which gets a bit tiresome after a point.

With a first-half that overpopulates itself with low-intensity horror, Petromax gets focus right from its pre-interval block, where the ghosts get a hilarious reality check. The quirks are used to a better extent, as they are used to mock the ghosts' generic antics rather than appearing as mere throwaway gags (One guy outdoes the ghost's theatrics with his loud acting skills, while the other is impervious to the spirits' devilish cries as he is deaf and suffers from night-blindness). The hilarious stretch is the most entertaining part of the film. Post the forty minutes of amusement, the film veers into a serious zone, as the ghosts unravel the person responsible for their death.

Though the climactic stretch is packed with a neat twist, the portion ends up being inconsistent with the lighter tone of the film. Petromax works marvelously well when the film parodies itself and the tropes associated with its genre. The narrative could have had more moments of foreshadowing that lead us to the denouement.

Tamannaah makes her presence felt in a brief role with a good performance. Apart from her, the stars of the Petromax are the performances by Munishkanth Ramadoss, Kaali Venkat, Sathyan and TSK. Their quirky, underdog act as the four perennial losers with humourous flashbacks is the film's biggest highlight. Despite unfolding only for a brief period, the humor is situational, and consistently involving. Add Yogi Babu and 'Mynaa' Nandhini to the mix, the horror-comedy becomes a complete riot. Special mention goes to Prem, whose calm demeanor lends more ambiguity to his character. Overall, Petromax entertains well solely through its amusing flourishes in the second half.