I'm in the UK and saw this at my local arthouse cinema tonight... What a total disappointment considering the amount of hype surrounding it, e.g. Cannes shocked! France giving it a rare 18+ certificate and people walking out at Frightfest... In truth, I imagine they walked out because it's total rubbish!
The first half has limited shocks or thrills and any interest is quickly lost within the first 20mins as the plot is clearly signposted right up to the start of the second half which is completely pointless violence, leading to an ending which can only be described as ridiculous.
Considering this has been branded as part of the new wave of French horror, believe me it can not stand alongside the likes of Frontier(s) or Inside. The former film at least was a homage to classic 70's shockers with the latter film having a raw moral element to it that leaves you devastated. Martyrs is just plain daft!
Apparently, the distributors simply don't know what to do with the film and therefore, it is going to be released in ONE cinema in London later in 2009 (no release date set as yet). Personally, I'd release it on DVD and hope for the best financially!