As you wander around the enormous mansion/laboratory of your reclusive, mad-scientist Uncle Quadwrangle, do take the time to pause the puzzling in order to scan the front covers of the various books strewn across the rooms: The Quark of Monte Cristo, The Half-Life of the Baskervilles, and Great Exponentiations. You see, after Kim Swift's success with the sublime Portal, it would be hard to understate the great expectations thrust on her newest creation. Even after coming up with yet another outside-the-box mechanic for Quantum Conundrum (the ability to shift between dimensions, each with their own physical properties), Swift's first-person puzzler risks being compared to and overshadowed by her earlier work, so can you blame her for stooping to puns?
She was right to worry: The storytelling isn't the only thing the two games really have in common. As in Portal, you're guided by a largely unseen antagonist—your amnesiac, misanthropic uncle, voiced by John de Lancie (every bit as playful as he was on Star Trek)—through a series of chambers that test the functionality of a new technology. As you work your way through puzzles, this character will berate you, and each time you die you'll be reminded of all the boring, adult things you, a 12-year-old boy, will now never get a chance to do. The early chambers of each zone (there are three, each with roughly 16 distinct levels) automate dimensional properties with the low-tech combination of dipping birds and the buttons they hit. As you progress, the game stops holding your hand and demands that you figure out how to best use your Interdimensional Shift Device (IDS) to swap between the Fluffy, Heavy, Slow, and Reverse Gravity dimensions.
Again, as with Portal, the trick of each level involves figuring out how to combine the tools at your disposal to reach the exit. The difference is that Quantum Conundrum puts a far heavier emphasis on platforming and reflexes, leading to more than a few frustrating puzzles in which you know exactly what you have to do…and yet can't. An end-game solution, for example, requires you to switch to the Fluffy dimension so that you can pick up a safe (it would otherwise be too heavy), grab another safe, jump on top of the first safe, shift to Reverse Gravity (so that the safe you're on rises, bringing you upward with it), shift back to Fluffy (so that you can grab the second safe in front of you), throw it, shift to Slow (so that you can properly time the jump onto the safe you've just thrown), and then toggle Reverse Gravity on and off (so that you can use the safe's momentum to essentially "fly" through the air). Like Mirror's Edge, the game rewards you for speed runs and efficiency within each level (though the online leaderboards rarely seem to load), but Quantum Conundrum is so downright masochistic in its expected precision that such goals seem hopelessly unattainable, especially in some of the longer, more laborious levels (that is, it's hard enough to complete the game as is, especially without a controller; the keyboard maps your dimensions to the difficult-to-hit Q, E, 1, and 3).
Frustrations and similarities to Portal aside, Quantum Conundrum's core mechanic is a rewarding one. Dimensional shifts affect more than physical properties, after all, and you may find yourself gazing at the ways the portraits on the walls cheekily re-skin themselves. There's perhaps a little too much handholding in the early game: revealing basic properties (heavy objects will break windows; they'll also block laser beams), hinting at obvious applications (using the "backboard" of a container to bounce a thrown object), or suggesting when to activate certain timed sections ("Go, go, go!"). But there's still plenty to marvel at and puzzle over in this 10-hour journey. (Two DLC level packs are on the way.) From time to time, Quantum Conundrum may find itself shifting into the shadow (dimension) of the Portal series, but it's not stuck there.