It's a great ride while it lasts.
You start off as a character who wakes up in what appears to be a comfort holding cell. A robot voice named G.L.A.D.O.S. comes over the speaker and explains to you that you are part of an experiment. After a couple of minutes of explaining, you get to be released from your cell and into the testing area. This is were you get your first glance at how amazing the Portal technology is.
After a few brief challenges, you get your fully upgraded Portal gun. Your Portal gun can shoot blue and orange Portals. It doesn't really matter which one you shoot first, either way you end up were you want to be. The Portal gun is very precise. The controls for the gun are very simple and the Portal literally goes to the exact spot you tell it to, as long as it is on an area that Portals can be on. After a while you'll probably start to experiment with your Portals. Odds are eventually you'll get your first glance at your character through a mirror effect with the Portals. But the real fun is when you shoot a Portal directly above you, and below you. This sends you into a never ending fall.
It isn't all just fun and games though. Every now and then a challenging puzzle comes your way, and it'll keep your guessing for a couple minutes. But the puzzles aren't very satisfying when you solve them. Usually it's just pushing some blocks around, knocking over turrets, and getting a little orb into its hole. After a while, it starts to get repetitive.
With the new and slightly improved Arcade version of Portal, you get a couple more challenging puzzles. Yet again, after you solve them it leaves you with an unsatisfying feeling. However, the time trials, the least steps, and the least Portal challenges are very satisfying when you complete them. You can earn either a bronze, silver, or gold medal depending on how fast you go or how little of something you use/ take.
Portal is a new and exciting game, and definitely a great ride from start to finish. After completion you may feel like you want more, but that's what the new challenges are for. You may not be playing much, but you'll have a great time every time you pick up the controller and mess around with Portals.
Positives:
+Beautiful graphics and amazing Portal technology.
+The new puzzles give Portal players from The Orange Box a reason to play
Negatives:
-Puzzles aren't very hard.
-To short of a story.