UNTIL DAWN puts players in the shoes of eight teens who reunite in an isolated Alberta mountain lodge one year after experiencing a terrible tragedy in that same location. The night gets off to a normal start with the group suffering nothing worse than a forgotten bag or a lost key. But it soon becomes apparent that they're not alone on the mountain -- someone or something is lurking in the snowy woods, and their lives are in real danger. Players control each of the eight teens in turn. They'll explore their surroundings and look for objects of interest while gradually moving toward objectives, such as a secluded cabin where two of them intend to spend the night together. The kids frequently chat while walking, providing insight into their relationships and backstories. Players are occasionally prompted to make decisions about how one character should react to a given situation, which can have an impact on a relationship or friendship and how the story plays out. As circumstances become increasingly dire, players are placed in situations in which they must quickly push buttons as prompted to make characters safely leap across chasms, climb rocks, or help others. Failure may result in death. Since there's no restarting or reloading (the story moves forward relentlessly, regardless of what happens), dead characters remain dead for the duration of the game. This is essentially an R-rated teen slasher movie turned into a 10-hour game. It's brimming with genre tropes, including character stereotypes (slut, nerd, jock), an isolated forest setting, gratuitous gore, and at least one obvious red herring. That said, it's also very well executed. The visual presentation is so rich and detailed that most players will be able to instantly recognize several members of the cast -- which includes Hayden Panettiere (Nashville), Peter Stormare (Fargo), Rami Malek (Mr. Robot), and Brett Dalton (Marvel's Agents of S.H.I.E.L.D.) -- based on their facial models and body language. These actors do a terrific job of eliciting emotions from the player, making us love, hate, or get frustrated with them. They seem like real people, and you'll likely care about them more than you would most video game characters. This makes their potential (and gruesome) deaths all the more jarring. You'll be sitting on the edge of your seat during action sequences, knowing that one slip of your thumb could result in a character's death, causing the rest of the characters to mourn his or her loss as the story marches on without them. It's a surprisingly heavy responsibility for a gamer to bear. It trips in a couple places. A noticeably slow frame puts a slight blemish on the otherwise superlative graphics. Plus, clunky controls for movement and exploration can lead to some frustration when you're trying to make your character go one way and he or she inexplicably goes another. But these issues can't keep Until Dawn from succeeding in its aim to feel like an intense horror movie that's been slyly and expertly transformed into an interactive experience.