Well in the spirit of WAZ"s algebra-related title, my take on the film can pretty much be summed up with this little equation:

WAZ = SAW - inventive death scenes + (added bleakness + deep meaningful stuff)

WAZ definitely ticks all the "beware - this is grim, gritty and depressing" boxes:

* dimly lit scenes and wobbly hand-held camerawork
* dilapidated buildings with dingy stairwells decorated with graffiti and bodily fluids
* squalid crack dens filled with vacant-eyed addicts
* brutal gang members with a love for the more colourful expressions in the English language...

Happy happy joy joy eh? Thrown into the mix is the pretty standard pairing of "jaded older cop who enjoys smoking cigs and looking miserable" and "younger, more idealistic cop with a vulnerable side". Together they set out to stop a killer with a fondness for torture and algebra (sounds like most of my old maths teachers frankly) and become embroiled in issues of revenge, morality, love and self-sacrifice...

If you"re expecting/wanting Saw-style scenes of twisted torture devices and the gruesome dispatching of victims, then you"re pretty much out of luck. Most of the nasty stuff is implied rather than blatantly right in front of you on the screen (although a moment where a victim has nails hammered under his fingernails is quite wince-inducing). The visceral factor only really ramps up right towards the finale, and is combined with the obligatory twist (which I actually found a bit daft).

The performances of Stellan Skarsgård and Melissa George as the leads are solid enough but I can"t say I ever felt that their characters were very engaging or particularly interesting. This was echoed by the film in general which did plod a bit in a lot of the scenes. Sometimes literally, with Skarsgard"s Eddie wearily trudging up a flight of stairs or down a corridor.

Overall, for me it"d fall into the "watch once and never bother seeing again" category, but if you"re after a thriller that focuses less on gore and more on being thought-provoking then give it a go.