Summary: I've played the PC version using the Steam game engine. I'll have to say the navigation and controls are more fluid with the mouse on the PC version, but it's still an awesome game on the Xbox. I love Portal because it makes you think before you play. This isn't the kind of game that you play for a few hours and then get bored. The challenges and difficulty escalate with each level.
Summary: Portal has won many awards since its launch in 2007, and when you play it, you'll agree that it deserves them. It's ingenious and compelling, a masterpiece easily at home in an all-time greatest games hall of fame list. Despite many recommendations from friends, I initially avoided getting this game for two reasons. Don't make this mistake! It's a fantastic game, and neither of my concerns proved to be important.
Summary: The stand-alone arcade version of Portal is a terrific little game and well worth the modest cost. If you've got the Orange Box retail game, skip this. But if not, or if you absolutely LOVED it in OB and want to get the extra challenges, go for it. Such a simple concept gets used in so many different ways that the entire game.