It's remarkable what a few adjustments can do. From instruments to user interface to gameplay options, one thing after another makes you nod appreciatively and smile while playing Rock Band 2. Rarely are these profound alterations, but taken together Rock Band 2 is now a much more cohesive experience – a fantastic platform all the better for its nearly infinite expansion possibilities.

It's unwise to go into Rock Band 2 expecting some decisively different game from the original. Even a practiced eye might have trouble distinguishing the two. You're really paying for two things. The first is a huge new selection of songs. Over 80 tracks ship on the disc, another 20 will be available for free in the first weeks, and literally hundreds can be purchased online from a library that has been slowly building since the first game's release. Previously downloaded songs seamlessly integrate into Rock Band 2's primary modes, and you can even import all the original Rock Band on-disc songs into the new game. Examining only the songs on the new disc, Harmonix has embraced the philosophy of all-inclusion. There's something here for everyone, and the music genres represented are all there for a reason – they are almost without exception great song choices.

The other reason to spring for the sequel is the game's tweaked structure. Progression is now united under one big touring experience. You make a band and always play with that group, whether you're going solo or playing with friends (online or in your living room). While out touring, you'll encounter dynamic band battles – multi-day events where your band vies for the top spot, both among your friends and against all the other players – all the multiplayer modes now seamlessly integrate between online and off. Getting into the game and finding the song you want is now easier, thanks to some clever UI reorganization. An increased number of special events and different hired staff options let you customize and hone your band's focus on fans or money. Finally, and perhaps most importantly for parents with young kids, a No Fail mode can be turned on to assure that the fun keeps going, even if every player isn't a rhythmic genius quite yet. The only thing that frustrates is the lack of a more straightforward way to unlock songs – you're now faced with occasional song repeats to get to later venues.

While they may not be game-selling features, a few smart additions further flesh out the package. A jukebox mode lets you listen to your music freely without having to play along. A drum trainer helps you improve your skills on the kit. The freestyle drum mode even allows you to drum along with any music you've downloaded to your console's hard drive.

I can't think of any person to whom I wouldn't recommend Rock Band 2. Playing alone, it offers a suitable challenge for any skill level. Playing with friends and family, it is one of the best social games ever made – a testament to the way games can bring people together to have fun. Sometimes good game design is about dramatic innovation. Sometimes it's about knowing what not to change. Harmonix knows how to do both.