Don't fix what isn't broken--the phrase best sums up the approach behind Rock Band 2, sequel to last year's innovative title from the music gaming mavens at Harmonix. While plenty of enhancements and additions mark this next installment for the budding franchise, Rock Band 2 is more about building upon the core experience that was so expertly crafted in the original. Playing through a couple tunes during E3, we're confident that it has what it takes to rock another set.

As with any music game, the most important thing is the soundtrack. Rock Band 2 promises upwards of 80 tracks on the disc ranging from 80s electro-pop to 90s grunge to modern hits. The diversity is even greater in this second installment, including a wide range of artists from The Who to Elvis Costello to System of a Down. There's bound to be something for everyone to enjoy and if there isn't, you can dig through all of the songs available from the first game and play those. In a surprising move, the game will offer backward compatibility with all songs included in the first game including any tracks you may have downloaded from Xbox Live or PlayStation Network.

Changes have been made to the structure of the game, resulting in a couple new modes and alterations to the main World Tour. You're now able to play World Tour online, although this comes with the revelation that online play won't be added as a patch to the first game.

Along with online play, it's now possible to switch instruments at anytime during a tour. In other words, you can play drums on one song and then swap it out for bass on the next tune. Joining the retooled World Tour is Battle of the Bands mode. Teaming up with three other locally or online, this inventive new mode pits you against virtual bands in ranked tournaments. Winning a battle means achieving a set score.

Solo Tour mode is out, replaced by Tour Challenge mode. This assemblage of various skill-based challenges allows you to unlock additional songs and events in a non-linear fashion. Instead of being shoehorned into playing specific tracks in order to progress through the game, you have the option of choosing from a range of challenges to move forward. The plan is to incorporate any songs you've downloaded into the mode, so you'll have those available as an option as well. Harmonix hopes that the new structure will empower you to access those tunes you enjoy playing, without having to slog through too much of the songs you don't like.