It's hard to overstate how heavily Saw influenced the Western horror scene after its release in 2004.
The decade prior had been the era of Scream, and while Scream itself was a phenomenal take on the classic slasher tropes, every self-aware copycat that followed seemed to be trying to wink and nod audiences into a coma. The Blair Witch Project opened a major door for low budget horror in 1999, and The Ring solidified PG-13 spooky ghost flicks as a horror mainstay in 2002, but by-and-large, R-rated horror movies were still characterized by irreverent teen shlock.
And then came Saw.
Saw revolves around two kidnapped men trapped in a basement room with a dead body and forced into playing a life-or-death "game" engineered by a psychopath named Jigsaw. While the movie received mixed reviews upon release (many of them negatively comparing it to the David Fincher-directed thriller, Seven), Saw became an instant hit nonetheless.
Comparisons to Seven weren't entirely unwarranted, though––not only did Saw follow a similar narrative involving a killer masterminding elaborate deaths reflective of their victims' sins, but both stories also featured huge twists. However, whereas Seven grounded itself in the police hunt for the killer, Saw anchored itself with the victims, firmly establishing itself as a horror movie as opposed to a thriller.
Unlike the vast majority of other major horror movies of the time, Saw wasn't fun and light. It didn't seem designed for teens to cuddle up to on a date night. Saw was gritty and brutal with a dirty aesthetic. It felt less like watching a polished feature from an established movie studio, and more like an underground indie.
In a lot of ways, Saw feels amateur with its shaky camera movements and arguably poor acting (Cary Elwes kind of overdoes it). But at the same time, that almost lends to Saw's grindhouse credibility. It is an extremely low-budget movie, made for a mere $1.2 million (on which it made $103.9 million in return). And while it was clear that first-time feature director and current movie mogul James Wan was still finding his footing, his talent at creating intense, evocative horror was readily apparent.
One of the most interesting things about rewatching Saw is realizing that the movie actually isn't very gory at all. Rather, Wan creates scenes that cleverly give the implication of intense violence without ever showing the worst of it. For example, Wan shows the corpse of the man who climbed through the barbed wire trap after the police find him, but you never really see the barbed wire actively cutting him. Instead, you get a flashback with quick camera cuts and intense shaking that implies the pain and fear of the experience without graphically depicting much. Similarly, the climactic scene where Lawrence saws his own leg off is actually relatively tame. We know that Lawrence is cutting through bone, but we really only actually see small glimpses of him cutting into shallow flesh. The rest is conveyed through camera movement and facial shots.
Then again, the brutality of the first Saw might be blunted a little by its sequels and successors, which leaned into the graphic violence angle and delighted in showing absolutely all the gore and bloodshed that practical effects would allow. In the same way that Scream's sequels and copycats failed to live up to the cleverness of the original, subsequent Saw movies largely discarded the intrigue and thoughtfulness (why are these two victims here and how will they escape?) and instead dwelled on increasingly disgusting "puzzle" devices for maximum carnage. And while there's a certain enjoyment in watching those, especially for a seasoned horror buff, it's hard to call any of the later movies "good."
A trap from a later Saw. This man is not escaping.Lionsgate Films
Moreover, Saw completely changed the horror landscape. Post-Saw, dark, edgy, adult horror movies took over at the box office with some copycats like Hostel but also quality movies like The Strangers. And in a sense, while the dark, gritty horror movie trend that Saw started could be viewed as a response to the formerly prevailing light teen fare of the '90s, the thoughtful, heady, conceptual horror of the 2010s (movies like It Follows) could be seen as a response to the visceral realism of movies like Saw.