Quantum Conundrum made me very happy for its duration, and then it was over, and it was just me at the menu screen having considerably less fun than I had been having previously. I'd passed through so many distinct states of being during the trip that I had forgotten how to do normal things.
It may not be possible to talk about Quantum Conundrum without discussing Portal. I'm sure they don't like that. This is what happens when you succeed, though: it colors expectations, which need to be addressed. Quantum Conundrum is the game equivalent of "the Sophomore Album."
I still feel like my initial observation was correct; we don't have a word to describe a designer's "style" that is distinct from "genre." Moreover, I think we might have the genre wrong anyhow; I'm fairly certain Portal and Quantum Conundrum are Adventure Games. Adventure Games of the classic form are still with us, and are arguably experiencing a resurgence, but they're not this. Portal and Quantum Conundrum are what adventure games would look like if the genre had never experienced a Dark Age: you manipulate your environment, and are rewarded with new environments to manipulate.
Quantum Conundrum doesn't have any intention of being a narrative tour de force, which is too bad, because this is no doubt what everyone expects. Portal was written by the industry's foremost writer of humor, which helps. There is one other person who could have done it, but he also works at Valve. Quantum Conundrum is purposefully, explicitly not trying to do that. These people are trolls supreme; click Do A Thing, for example. The game is based on a pun. I've never played a game that felt so much like it was teasing the player.
(Just as an example, near the end, there is a completely simple room which meets only the barest definition of a "puzzle," the mechanical equivalent of turning a knob. But the mental apparatus I had constructed for solving Big Problems could not manage this tiny one; it was like trying to make toast with the Large Hadron Collider. These people are fucking goofballs.)
Portal rarely asked you for any significant platforming acumen, short of momentum jumps; here, you'll be asked to hop from hell to breakfast, or onto something you just threw in another dimension, but don't worry about it because you can slow time to a crawl and make such leaps at your leisure. It's got precision, but it's not really "about" timing. At the same time you accomplished incredible feats, with the help of your cheater dimension glove. The pride remains.
In grand Adventure Game tradition, you have an "inventory" but it primarily consists of the dimensions you have access to. There are very few levels where you have access to all of them, but when you do - when you have that kind of control - you stand astride the world. You are capable of the most incredible shit: you can turn almost any object into a flying carpet, just for starters. I loved this part, but the slab at the end where you have all the tools isn't long enough in my opinion - it isn't explored enough. I don't doubt that it's coming, though; the version I purchased includes two packs of DLC, which I understand are brutal. But yes. Then the game just... flies away, like a superhero needed desperately across town. All you can do it sort of wave at it. Oh! And feel empty.
"Enjoyment" is a fairly cerebral process for me. I'm like the chocololate taster lady; it's a physical process, it's something I'm consciously doing. But around the edges of Quantum Conundrum, there is always a kind of buoyancy that raises at least one corner of the mouth; it has a disarming quality.