4 years ago, Quantum Conundrum would have been the game everyone was dreading; Portal for kids, the humor neutered and the story piecemeal. Now, judging by the anticipation for the game, we've warmed up somewhat to the idea, and are quite willing to meet it on its terms, if it's done well.
And done well it is; the puzzles are masterfully structured and designed (though I feel the Source engine would be better suited for the physics required than the ubiquitous Unreal 3) and retain the perfect balance of challenge and reward, inducing that great feeling when everything clicks and you've outsmarted the environment. Since this is the game's core, this goes a long way toward redeeming the game's many flaws and making it genuine fun, so I do recommend the game for this if nothing else.
The bad news is that the game is a serious let down from Portal in the context department. Portal 2's story and visual design are what cemented it in the public consciousness, and there's the unpleasant feeling that Airtight has been painting safes over the cubes, doglike happy faces over the dispenser vents, and drowning out Ellen McLain's deadpan gallows humor with veteran actor John de Lancie's much more friendly and childlike comedy, and the stark, flat laboratory aesthetic with a much brighter and rounded feel that reminds me of a cross between Bio Shock
and Scribblenauts. This perhaps best represented by Ike, a fuzzy green thing that exists solely for his own sake and to justify the occasional annoying internet meme reference.
Quantum Conundrum's best story aspects are its original ones - the paintings that your faceless uncle elaborates on (and change along with the dimension you're currently in, a very good touch), and the death screens that hearken back to Sierra adventure games, giving a randomized "Thing you'll never experience" along the lines of "Lying on your taxes...a little" and "Reading about current events just so you know what to be outraged over", which provide the best humor to be found in the game.
Perhaps the entire experience of Quantum Conundrum is summed up by its ending song: An upbeat, bouncy alternative rock tune that would be good on its own, but gets annoyingly repetitive and (because the game is made by huge conglomerate Square Enix, necessitating very long credits) overstays its welcome.