How do you follow up on a four-hour pack-in title that blew up into a phenomenon that defined a year-plus of gaming culture? Valve Software decided to flesh out the concepts pioneered in "Portal." Without turning the page, the team has painted a much richer picture that seizes your attention in a steel grip even if it's telling a similar story.

Like the original, so much of what makes "Portal 2" special is in the execution and the originality of standing in Chell's shoes and experiencing her destiny. Any spoilers would seriously detract from the game -- not because the plot relies on contrived twists but because Valve has leveraged the interactive experience perfectly. Weathering the taunts of a sadistic AI as you're trying to survive its deadly challenges is unlike passively watching HAL-9000 try to kill off meddling astronauts. Gruesome depictions of abandoned experiments take on a new horror when you're desperately avoiding a similar fate yourself. The dialogue's pitch-perfect delivery is half of "Portal 2's" genius, and it would be a shame to spoil the brilliant comedic timing or any of the other many nuances Valve so painstakingly crafted in this review.

This isn't to say that "Portal 2" takes itself too seriously. Descriptions of violent, painful death are played for a laugh more often than not. GLaDOS' blithe disregard for human suffering is again a recurring comedic theme. The touch of gravitas here and there is just enough to ground the writing and serve as a contrast to "Portal 2's" goofy world. I would have preferred Valve to play it slightly straighter and give a look into what catastrophic events led to the current sorry state of Chell's world, but that's the sci-fi nerd in me talking. We don't need to know why the Enrichment Center is; that it is trying to kill us is enough.

I was concerned that I would tire of "Portal's" one-note shtick, however amusing, over the course of a full-length game. The single-player adventure stays fresh with the addition of two major speaking roles and a few different environments, as well as the masterful pacing of the original. I never once thought I'd place GLaDOS second on any list of "Portal" characters, but J.K. Simmons' character surpasses the malevolent AI even though she's as amusing as ever. I was never bored with the dialogue, settings or puzzles.

Co-op play is more mechanics-driven, with occasional bits of hilarity injected by GLaDOS' amusing attempts to sow enmity between the two of you. The puzzles are ingenious, and the simple ability to put a marker in the game world makes plotting strategies out smooth and easy. I wasn't sure about co-op puzzle-solving beforehand, but "Portal 2" made me a rabid believer. Do whatever it takes to find someone to tackle these challenges with. They're that good.

As for the puzzles themselves, they're wonderful. "Portal 2" has fewer agility-driven obstacles, so less dextrous gamers shouldn't find themselves stuck on anything for lack of stick-flicking ability. The new elements are each great in their own right, and they work together beautifully.

The game's quality stays consistently outstanding throughout. I would have loved to see something unique done with the story. I would adore seeing "Portal" stretch its wings beyond being a series of puzzles that almost always have one correct solution waiting to be found. That said, the next game I want to play is a second run through of "Portal 2," because the formula is excellent and brilliantly executed.

PORTAL 2

  • 4 out of 4 stars
  • Publisher: Valve Software/Electronic Arts
  • Systems: PlayStation 3, Xbox 360, PC
  • Price: $60
  • Rating: Everyone 10+