It’s another film involving an exorcism; something that writer-director Scott Derrickson is passionate about, having penned and directed none other than The Exorcism of Emily Rose, and the relatively comparable horror Sinister. The problem with dealing with the same supernatural subject matter, is Derrickson gets compared with his last demon-exercising flick, creating a rod for his back in having to up his game. Sadly, it’s not enough in this day and age to throw out the usual moniker “based on a true story” because it currently feels like every scary movie is. However, Derrickson has tried something a little different by blending the cop and horror genres and positioned the ever solid Eric Bana as the lead.

Based on real-life cop/occult investigator Ralph Sarchie’s accounts, Bana is Sarchie, the NYPD cop, too. Things get a whole lot sinister for father-of-one Sarchie after a dead baby is found in a dumpster and he is then called to Bronx Zoo with wise-cracking partner Butler (Joel McHale) to investigate a mysterious, deranged woman on the loose who has just thrown her toddler to the lions. It later transpires that the mother is married to one of three Gulf War veterans who were dishonourably discharged from the Military on the grounds of post-war misconduct, possibly through drug abuse. However, Sarchie begins to unravel the mystery of their mental demise, guided by renegade priest Mendoza (Édgar Ramírez), leading him into the path of possession and the Occult and ultimately, the Devil incarnate.

It’s true; Derrickson’s latest spook fest is far from perfect, complete with questionable plot antics – some bordering on the hysterical (unintentionally). Indeed the thing that keeps the status quo grounded is the promise of ‘real-life’ events inspiring the screen story, though it’s obvious what’s been hammed up for Hollywood – the exorcism portrayal in particular. Things are also made all the more credible by Bana who always delivers a respectable performance (bizarre accent aside). Adding the cop drama angle indeed accentuates this, and in Derrickson’s gritty, dirty and disheveled NYC the outlook for us is bleak as Sarchie stumbles upon the lowest of the low of humanity nature – something he later confesses to worried yummy mummy/wife Jen (Olivia Munn). Hence, the scene is nicely set for a socially-conscious, dark and sinister cop horror.

Well, not quite, unfortunately. Although highly watchable – if you discount the overkill of prompted jumpy scares that it seems to favour, often including cats, the whole puzzle of what’s going that’s quite enthralling at the start easily slides into type: The non-believer joins forces with the believer and has his cynical views changed through witnessing the paranormal in full force. Indeed the outcome is predictable, but the path goes from intriguing murder-mystery puzzle to plain old exorcism, this time in a police station that appears to be ‘deaf’ to all the howling, demonic rage in one of its interview rooms. The saving grace is the unsettling and unpleasant setting to remind us of the bigger evil at play, plus some exhilarating chase scenes and sheer brutality, often triggered by stereotyped Sean Harris as demonic leader/decorator/war veteran Santino, an actor who does vicious villain or pathetic victim so effortlessly (and looks the spit of Darth Maul in this).

Deliver Us From Evil is an apt title, considering the line-blurring human and supernatural malaise Derrickson’s film explorers. It also nicely stews the psychological part, suggesting how much is in a damaged mind and how much is for ‘real’. Trouble is, although it has all the elements – and cast – of being a great thriller, criss-crossing genres with ease, it does sport too many horror tropes (cue haunted basement for one), as though the filmmaker doesn’t have the power of his own convictions to boldly go where he hasn’t gone before, instead running back into the lure of his own comfort zone. Perhaps, actually showing the exorcism cheapens the psychological mystique/terror Deliver Us From Evil commendably builds? Just a thought…