If you put Adrift, Very Bad Things and - at a pinch - Morvern Callar into a blender, the resulting concoction would look a lot like Donkey Punch, the title of which refers to a dangerous sex act rather than a drink with a kick.
The opening reels offer fun-in-the-sun with a bonus sense of impending doom as Tammi (Nichola Burley), Kim (Jaime Winstone) and Lisa (Sian Breckin) get together with blokes a few social classes above them and slightly creepy for it - Bluey (Tom Burke) patters in a stoned dickhead’s idea of street argot (eg: calling Ibiza ‘Beefa’), Marcus (Jay Taylor) is about to go into the Marines, Josh (Julian Morris) has just graduated as a lawyer, and his older brother Sean (Robert Boulter) acts responsibly but is still more loyal to family and friends than casual pick-ups.
When Bluey explains that the male orgasm can be heightened by a karate blow to his partner’s neck during climax, Kim asks, “What’s in it for the girl?” and he sincerely deadpans, “I don’t understand the question.” This sets the tone for Act Two, as the surviving girls get hysterical but the boys go into scheming, wheedling overdrive - the culprit becomes calculating, trying to manipulate his friends into covering up his crime, while his friends make all the wrong moves. Like a lot of ensemble horrors about a situation spiralling out of control, Donkey Punch works for most of its running time but slips into a contrivance-ridden formula for the final act, which features a succession of gruesome deaths (an outboard motor and a flare-gun are among the improvised weapons, but the yacht is usefully equipped with a shotgun).
The build-up and initial complications are suspenseful and horribly believable, with cross-purpose banter (“It’s all going to plan”) setting up everyone’s selfish agenda and grounding what they do when things get out of hand - although it’s hard to warm to any of these people, with the ostensible victims scarcely more sympathetic than the deeply horrible villains in the pack. First-time director Olly Blackburn, who co-scripted with David Bloom, gets good work from an outstanding young cast, and if no-one quite stretches to the finale, it doesn’t take away from how good they are during the build-up.