Interesting article with some interesting points.
I have to say, I've never played Half-Life, and most likely never will, so the game Portal reminded me most of was Super Metriod.
It's just you and one big map to explore, dozens of puzzles to solve, enemies to fight, and bosses to bring down before you can get to the shocking and exquisite showdown that, to me, not even Portal could match, though Portal does have the better end credits.
I could pretty much retype your article and replace every mention of "Half-Life" and "Half-Life 2" with "Metriod III" and "Metriod IV" to best express my feelings on the subject, but that's a bit too much work, and my point has been made already, anyway. (I hope)
Also, for the most part, in the gaming world, less is rarely more, and it's only a very few extremely well crafted master works that could ever hope to get away with that motto.
Let's face it, if Portal was 6 hours instead of 3, we would love it even more, but only if those extra 3 hours were as well done as the first 3, which is a horrendously difficult task, which makes me wonder what they plan to do to top it in the sequel.
And though you may feel that knowing more about what happened, why it happened, and what will happen next isn't worth knowing and will spoil your memories of this great game, I say ,"tell me, I want to know!" because you just know that, even if it's disappointing and ruins the dystopia world feel you like so much, you still want to know more.
What will happen next, what's the next part of the story, how's it all gonna end?
Cause you know, a test subject with a very expensive, rare and near priceless piece of technology escaped her maze, Aperture, whoever they are, isn't just gonna stand there and let her go, they're gonna try to catch her, with force, and I can't wait to see how they plan to make puzzles around avoiding mercenaries out to hunt you down, possibly in that forest we all saw before the blackout....
Yeah, it won't be the same game, but you know what?
If you want the same game, than play the first game, while I can't wait to play the squeal.