The addon works just like Bejeweled -- you can load up the window whenever you want just by typing "/peggle." It's a little larger than the Bejeweled window, though there's a little more going on. While Bejeweled is just about matching up gems, Peggle is a physics-based game. You drop little balls down through a screen full of pegs, and either hit regular blue pegs (which just add to your score), green pegs (which give you Peggle Master powers -- more on that in a second), or orange pegs (which you need to clear out to complete the stage). The gameplay is almost completely unchanged from that of the regular Peggle game -- you still get a free ball for sinking a shot in the bucket roaming around the bottom, and you can rack up score multipliers by hitting lots of pegs in one shot. There are twelve stages total, all based on different locations in Azeroth, and I didn't recognize any of them from current Peggle games, so I believe they're all new.
There is one little feature missing from the usual Peggle action, and that is that there are only two "Peggle Masters" to choose from. You either get Bjorn's guide, which will tell you where the ball will go after it makes a bounce or two, or Splork's space blast, which lights up all of the pegs around the green peg when you hit it. There are usually ten different abilities like that to choose from, but the eight missing abilities are made up for with "Peggle talent points" -- completing stages will give you talent points, which you can spend elsewhere in the addon to actually change the gameplay. Put two points in "Style for Miles" and you'll increase your score from style shots by 4%. Spec all the way up to "Rolling Ignition," and landing the ball in the bucket after you hit a green peg will give you another green peg. Shots can even "crit" for bigger scores, and talents can change those crit percentages as well. Just like with the Bejeweled addon, it's a really fun mix of WoW and Peggle gameplay.
Talent points don't count, though, when you're playing other big bonus in the Peggle addon: multiplayer. Duel mode allows you to challenge another WoW player with the addon installed to play a one-on-one round of gameplay -- once you both agree to the duel, you each get to play your own round, and then the addon automatically tracks and compares scores afterwards. For more than two players, there's a Battle Mode will let you bring in multiple people (I had up to eight people invited, but couldn't find a limit, since that's all I had on my friends list at the time) for a huge battle that is ongoing for anywhere from 12 to 48 hours -- sometime within the time limit, everyone plays whatever amount of shots you specify, and then the player with the highest score at the end wins. It's not real-time multiplayer (you don't get to watch other players' shots), but both Duel and Battle modes are really easy to use, and will let you and your friends lay claim to who really is the best Peggle player in Azeroth.
And for the ultimate stakes, there is a /peggleloot command included with the addon. If you are Master Looter in a raid or group, and type "/peggleloot" in the chat window, everyone in the raid with the addon will get a one-shot challenge from a random stage, and whoever scores the highest with that ball wins the item. Raidleaders, it's up to you, of course, but I know I will join a Peggleloot raid any day of the week. I'd much rather compete at Peggle than count on any /roll.
Presentation on the addon is terrific -- they've faithfully recreated all of the Peggle sounds and visuals (and yes, Extreme Fever is just as satisfying as ever, though I bet it took some crazy LUA coding to get it done right). I did have a few qualms with the physics system -- while everything worked as well as you'd expect most of the time, I did find a few places where the ball bounced off the bucket when it clearly should have gone in, or got stuck on a peg in a strange way. When you consider that all of the peg-bouncing gameplay is taking place in a free addon, that's definitely forgiveable, but it wasn't any less frustrating. I have no doubt that Fromwiller did the best he could do with the physics, and he did a great job, but there were still a few hiccups during gameplay that obviously wouldn't be in the full game.
That's hardly a negative, though, when you consider everything else that's in here. We can't recommend a download enough: this is a great addon, a great game, and all glory to PopCap for not only giving us these two gifts for free, but giving an up-and-coming addon developer a job while they're at it.
Next up, as long as they're taking requests, we can haz Bookworm maybe?