The downloadable version of Bejeweled Blitz plays exactly like the Facebook version you know and love, asking you to match as many sets of colored gems as you can in one minute. For those making the switch from Facebook, the game uses Facebook Connect so you can transfer your coin balance back and forth and still brag about your scores to your friends list just like before (You can also play the downloadable version offline, for those times when you don't have an Internet connection).
The downloadable version also adds some interesting secondary goals to the mix, including stackable badges for in-game accomplishments (destroy X gems, score X points in one move, explode X special gems etc.) and a leveling system based on your total career points. The new version also includes some welcome graphical and audio enhancements that make full use of that 3D graphics card you spent so much money on.
A free trial version will get you sixty minutes of play, but you'll have to shell out $20 if you want to play past that. If that sounds high for a game you can play for free on Facebook, consider that your $20 also gets you a million in-game coins, enough to purchase over 1300 of the game's most expensive "boost" power-ups. That should be enough to last you, oh, a week or two, considering how freaking addictive this game is.