Most of the way through the film I was thinking that it was a pretty run of the mill, bog standard slasher flick, better than Wolf Creek (although pretty much every other film ever made is better than Wolf BOOOORRRING Creek), but not really doing anything that original apart from making the lead a lesbian that doesn't get naked and get it on with another lead female (had Eli Roth directed it could be a different story).
Then it reaches it's climax, and I was caught unawares. Apparently there are clues throughout, although clearly not in a good Sixth Sense way, as I didn't really pick up on them, there was a bit of one at the top but that's it.
Unfortunately the latter part of the film doesn't really work for me, mainly because when you look back very little of what's happened previous makes any sense in this new context and by the end it still hasn't really done anything that I haven't seen before in other films (I'm not gonna say which cos that'll give it away) and to be perfectly honest the end of Aja's The Hills Have Eyes dicks on this, which it shouldn't.
And thank Christ it's called "Switchblade Romance" over here 'cos "High Tension" sounds like a Van Damme movie!