Ok, I finished Portal last week, and I have to say, I was VERY underwhelmed. All this talk about "changing the way you view space" reeally overhyped the game.
Basically, the game boils down to three moves:
Jumping into a portal to jump high, jumping into a portal to jump forward, and forcing an orb into a portal.
The game was ridiculously short, and while the humor and other wraparounds were entertaining, they could not hide the lack of depth in the main game. Braid, a game often compared to Portal, was a game I enjoyed MUCH more, because it was possible to LOGICALLY figure out the optimum solutions. In portal, some solutions actually require cheating (Many of the challenges require glitch-exploitation, or pixel perfect shots/timing).
I expected the challenges to really fill out the game, and I must admit, the "least portal" challenges are kindof neat, except when they require ridiculous moves. The other two challenge tpyes, least time and least steps are ludicrous. Least steps is wretched because it counts ALL steps, INCLUDING involuntary ones. A *Step* should be defined as pressing the "W" key long enough to move your character forward. The least time challenge turns the game into a generic twitch game, which goes agaisnt the theme.
So really Portal deserves TWO scores. I will borrow from figure skating and award 9/10 for artistic merit, and 6/10 for technicality. That works out to a 7.5/10, which sounds perfect.
Flame away, but you know, as always, that I am right.

Actually, I think that is a pretty fair review of the game. I personally wasn't really underwhelmed by the game, but I think my expectations of it may have been a bit lower than yours. I expected nothing more than a FPS/puzzle hybrid with a unique mechanic and that's pretty much what I got.

I thought the portal flash game was leaps and bounds better.

Honestly, I've never played Braid, though it has been strongly recommended to me in the past. I'm sure I'll eventually get around to trying it out.

Its a good little game, just don't expect it to redefine the way you think of the universe

I'd really like to see some publications adopt this method. But that would upset poor Metacritic.

Suppose I could agree with you, apart from the "glitch-exploiting". Can't think of a single time I had to do anything like that. I was severely disappointed with Braid though. To me, the game just felt far to pretentious for it's own good, trying too hard to seem 'artsy' and cerebral. It wasn't hard, it was just... too annoying in it's presentation.

See, that's your problem. You listen to people.
Don't do that :)

Portal "changed the way I view space", but more for what is possible in future games. Portal felt like practice for those games.

Yeah, I thought of it has a tech demo of sorts, a way to demonstrate how Valve could build on this. I didn't think of it as a game.

Exploiting glitches? What? (Maybe you just hadn't figured it out right? :P)
But hey, it's a lovely little game with heaps of charm, style and a completely different logic. Yes, just like Braid. And yes, I have played both, and yes, Braid is much more challenging.
But, download Portal: Prelude, beat it, and then come back. I have yet to beat the third level, lol.
Oh, and cake.

I never needed to be pixel perfect or use exploits in Portal (as in game code exploits. The whole point is to exploit its warped physics). You must have been doing something wrong.
It was too short. But then it started out as Orange Box filler content that people loved. So Valve released it as a budget title in its own right.

Same with Mirror's Edge really. It would be nice to see other games use what these games brought to first person gaming without solely focussing on portals or parkour.

Having to resort to "pixel perfection" or abusing glitches is usually a sign you're going about the problem the wrong way, or that you're attempting the "Least Portals" challenges, or that you're trying to line up a portal with an orb when you have no actual depth perception on a screen (Grr...) - most of which are designed around pixel-perfection. (Isn't the general idea about how many corners you can cut with those?).
Overall, though, the challenges range from damn clever to mind-boggingly frustrating; usually the latter due to the lack of "portalable" surfaces on most levels - long hallways really mess up your nerves for "Least Steps".
I still love the game, though. It ends just as it's getting warmed up and stuff, but I love it nonetheless.

Heh. Those are somewhat my sentiments regarding those 2 games too. With Braid, I couldn't give an arse what the story was about to even carry on, even though I liked the concept. I wasn't really underwhelmed by Portal - hell I thought it was one of the most awesome games I played that year, despite the short length - but it wasn't like "ZOMG BEST GAME EVAR" the way I saw people from other boards claimed.
To me, Portal was a fun, cute, charming little game that prevented me from throwing out the Orange Box in frustration (not spectacularly fond of Half-Life 2).