It's hard to overstate my satisfaction

Portal is one of the most completely great gaming experiences I've had in forever. It's a first-person puzzler that can be beat in one sitting and it has more depth, innovation and wit than games with ten times its scope.

As a test subject of Aperture Science, your goal is to navigate a series of puzzles using a hand-held device that can create two-way portals. The portal mechanic is genius (you can see it in action in this demo reel).

One of the fun things about the portals is that momentum is conserved. So, if you put two portals on the floor and drop something through one, it will yo-yo between the two. You can use this same principle to execute huge jumps, fall forever or set up a perpetual cascade of a single object.

You are instructed in the use of the portals by the disembodied voice of a computer named GlaDOS. As a silent, largely anonymous protagonist, Portal is as much GlaDOS's story as it is your own and to say too much about her arc would spoil the game.

Suffice to say, I found the unfolding and eventual conclusion of this arc to be very satisfying. In reading user reviews of Portal, you'll see a lot of comments about people 'beaming' or 'glowing' once they finished the game. I experienced the same thing.

A big part of this experience is the end credits which is being rightly hailed as the best video game credits sequence in some time. Ocarina of Time is the only game that had as big an impact on me.

While you can check out Portal's ending online, to do so would spoil the game. I highly recommend picking it up so that you can experience it first hand.

Update: Rabbit's review is really good. But also highlights why talking about this game kinda ruins it for those who haven't. A lot of the joy was that it was so unexpected.