Belfast director Jon Wright's latest feature is 'daft and gory enough' to warrant a viewing. Four tentacles up

There has been a bit of a boom in Northern Ireland-made horror films over the past few years. From the relatively high-budgeted likes of Waz, Shrooms and Hammer's Wake Wood to the DIY efforts of Yellow Fever Productions, it seems Belfast's dimly lit backstreets and the surrounding unspoiled countryside are conducive to an evocative horror movie shoot.

The latest to take advantage of the country's locations, not to mention our homegrown filmmaking talent, is Grabbers, an Irish-produced monster movie directed by Belfast man Jon Wright, who previously made the decent teenage slasher flick, Tormented.

Marketed as a horror comedy, the producers would clearly like Grabbers to be Tremors at sea, or a Craggy Island Gremlins, but it's actually closer in tone to John Carpenter's The Fog or The Thing, with its malevolent force menacing booze-soaked small-town folk in an isolated location.

That isolated location is Erin Island, a fictional backwoods off Ireland's west coast. Scenes of the port were shot in Rathlin, whilst Donegal stands in for Erin's windswept beaches, and it's all highly effective. Penned by Cork native Kevin Lehane, Grabbers is atmospheric and surprisingly subtle, especially in its episodic early scenes.

A pod of whales washes up dead with mysterious injuries. The crew of a fishing boat disappears. A local lobsterman (Belfast actor Lalor Roddy) catches a strange, octopus-like creature in his trap. A lot of this takes place at dusk, with Wright bathing everything in eerie blue light.

There's also a nicely designed central beastie – indeed, beasties – which bucks the trend of computer-generated creatures being overused and completely annoying. The effects work holds its own against much larger pictures, and Wright knows when to show the many-tentacled, tongue-lashing terrors and when to let our imaginations run away with us.

There are several genuinely suspenseful moments, as well as some humour (the climactic pay-off lines may not equal, 'Smile, you son-of-a-bitch,' for quality, but they make up for it in quantity).

The main problem is that Grabbers' advance publicity gives away the pivotal plot twist, so if you want to enjoy the film fully you'll need to avoid the posters, the synopsis and indeed the rest of this review.

The big reveal, then, is that the blood-sucking aliens are allergic to alcohol, and so the islanders must stay drunk in order to survive. It's a neat idea, but could have been developed in more interesting ways. Where are the abstinent islanders who become monster food, for example, or the creature who develops a liking for the hard stuff?

The locals hole up in Erin's only pub in order to survive the night, but before you can say, 'You're going to need a bigger bottle', the action has switched to the cave where the 'Grabbers' have laid their eggs.

Everything starts to come off the rails at this point, as Wright rushes to wrap things up. A key character, a marine biologist played by Russell Tovey (the werewolf in Being Human), is bizarrely never seen again after Wright has taken some care to introduce him, suggesting he was only there to spout exposition.

Still, it rattles along, with engaging lead performances from Richard Coyle, as Ciarán O'Shea, the sardonic, sozzled local Garda, and Ruth Bradley, last seen in ITV's Titanic mini-series, as Lisa Nolan, a by-the-book young officer sent from Dublin to cover a shift on the island.

Their romance is believable, though there's probably a touch too much character development for the target Friday-night crowd. Elsewhere, it's nice to see Derry~Londonderry's Bronagh Gallagher, as the pub's earthy landlady, do some acting again instead of launching stuff down the Oh Yeah Music Centre.

Grabbers is a decent B-flick, perhaps not destined to be Ireland's answer to Shaun of the Dead, but daft and gory enough to – ahem – grab horror fans' attention for an hour and a half. Four tentacles up.

Grabbers is on general release now.