There are a few recipes for survival horror that I've learned from the movies. A good survival horror has the following:
1) Emotional and psychological conflict. By having some underlying conflict between two characters, we set the stage for a mental or physical breakdown of societal mores. This conflict usually comes to a head under severe stress. For example, in The Thing, the scientists and military personnel have a philosophical dispute on how to conduct their mission. In Predator, Dutch and Dillon have a disagreement as to the nature of their mission. All these issues boil long before a monster shows up.
2) A hostile environment. The environment can be anything from the arctic (The Thing), to the ocean (Jaws), to a jungle (Predator). The hostile environment exerts pressure on our protagonists, forcing them together and preventing them from easily escaping.
3) A monster. Be it a shapeshifting creature (The Thing), a great white shark (Jaws), or a star spanning alien on safari (Predator), the monster sows discord and divides loyalties by creating an immediate sense of urgency.
Stephen King uses all these elements to great effect. But even with all three, authors often screw up the formula by having a weak conflict (if the characters aren't fleshed out enough, who cares if they die?), an environment that's easily escapable (why doesn't anyone ever call for help on their cell phone?), or the monster being cheesy (killer tomatoes? RUN FOR YOUR LIFE!).
I'm pleased to report that The Descent hits every note perfectly.
Three women, Sarah (Shauna MacDonald), Juno (Natalie Jackson Mendoza), and Beth (Alex Reid), a veritable trio of female empowerment, successfully complete a whitewater-rafting event. The suspicious nature of Juno's relationship with Sarah's husband is subtly portrayed through glances and facial expressions alone. When a car accident kills Sarah's husband and daughter, we have the grounds for a terrific emotional conflict.
Fast forward to one year later: our protagonist decides to rejoin her two companions in another bonding experience by going "caving." Three other women join them. We have the sister team of Rebecca (Saskia Mulder) and Sam (MyAnna Buring), the older of the two being the more experience spelunker. There's the confident hotshot, Holly (Nora-Jane Noone), who rushes into everything with abandon. And then of course we have our other two characters, the supremely confident Juno and Sarah's friend, Beth, who dreads getting older and seems to have the most common sense of the bunch.
Off they go, into the caves. Only it's not just any cave, it's an unexplored cave that's only been recently discovered. The terrain prevents easy ingress or egress and for much of the movie, the foreboding nature of the cave system is as much a danger as the monsters.
Eventually, the monsters show up. I won't give away any details other than to say that they are terrible to behold. The arrival of the beasties gives us the final piece of our survival horror movie.
The Descent is beautifully shot; director Neil Marshall (he of Dog Soldiers, the best werewolf movie EVER) experiments with different forms of lighting, including red flares, blue phosphorous, green glow sticks, and yellow torches. Flooding and cave-ins are around every corner, and we never forget that our protagonists are stuck in a cave.
The characters are equally engaging. Although it's clear from the beginning who will survive to the end, it never feels forced. People die horribly, monsters get their comeuppance, and the conclusion leaves us with the certainty that violence is no way to solve anything.
Lord John Whorfin once said that character is "who you are in the dark." We get the answer in Descent. Despite the attractive actresses playing the roles, this movie is literally a descent into the dark recesses of the soul. What they find there ain't pretty.