Of the five stellar games collected in Valve's new Orange Box, Portal should make the most jaws drop. At heart, it's a puzzle game built around the "portal" mechanic, which lets you blast a pair of holes onto any two surfaces and teleport between them—for example, to get across a room, or drop on top of a high platform, or blip around an insurmountable barrier. Portal adds this to the standard repertoire of sliding platforms, tripable switches, and near the end, robotic gun turrets that whisper playfully, "I see you!" (When you knock one down, it adds, "I don't blame you."
That kind of detail is what makes Portal so intriguing. You're cast as a test subject in a strange, gigantic laboratory. An erratic, musical robotic voice leads you through a series of "tests," and the narration is hilarious and menacing. What's really going on here? What's a test and what's a malfunction? And what is Aperture Science Laboratories, anyway? Players' expectations, trust, and sense of free will are razed with grace and humor. Even when you spot a trick, you wind up falling for it—after all, gamers, like paranoids, are trained to pay attention to everything. (To get even more meta, Valve's Steam engine gathers data on everyone who plays the company's games: All those security cameras really do watch your every move.)