this devilishly ambiguous thriller leaves viewers to decide whether to take the conventional or the less-traveled tunnel through its narrative network - and the results are a stylishly bloody descent into madness, murder and hell itself.

So thoroughly coated in over-the-top blood and guts that even veteran genre fans will likely be astounded.

Japanese director Ryuhei Kitamura, who kicked off his career with 2000's impressive micro-budget zombie flick Versus, delivers plenty of stylish visuals and an admirably unrestrained attitude to gore.

The film’s tone is severe and handled with the utmost seriousness in every scene. So why was I laughing?