Your enjoyment of Rock Band 2 will be dependent on which songs you have the most fun with.
Veterans will also welcome the ease of starting a quick local multiplayer session. No more accidental screen transitions because of shifty players who love feeling the tactile buttons on their instruments.
Rock Band 2 (RB2) has also become even more party friendly, especially to newcomers. Those who were intimidated or never had the guts to embarrass themselves in the original can now feel at ease. The No-Fail mode now allows people (who know and love their songs) to play with their friends without getting their band kicked off the stage.
One improvement that has been easily overlooked by many reviewers is RB2's song synchronization. In the original, calibrating the instruments to sync up with your TV and sound system was combined under a single adjustment. This is a case where you can hear the song's beats but the video is not synching as well or vice-versa. Now, RB2 separates video and sound into two different calibration systems. One calibration system will have you listen to a beat and strike a note based ONLY on what you hear. On the other system, you are synching your button presses or drum strikes with a video of a metronome moving back and forth without sound.
This kind of synchronization goes a long way for those who have elaborate home theater setups, especially for those who play their songs at the expert level. Try playing any song on expert between RB1 and RB2. You will see the difference. This sychronization trickles down to the other gameplay levels and makes the experience more enjoyable.
RB2 also offers a quickie version of this by allowing allowing the instruments to auto-calibrate via the instrument's microphone. Cool stuff.
From a single-player standpoint, RB2 is much more fast-paced in touring cities. RB2 has accomodated veteran players in a better way. Accessing more songs and cities is no longer a tedious experience of beating a number of songs but by how well you mastered each song. Mastering the first few songs gives you fans. The more stars you earn the more fans you get. The number of fans determines which songs and cities get unlocked along with extra goodies like cash and clothing. Beating the first few songs like "Eye Of The Tiger - Expert" with 5 stars will get you noticed and touring around the nation quickly.
Battle of the Bands mode, which lets two bands go head-to-head is a nice new option but it's setup mostly for online play. It's great as long as you know the people you are playing with. It would've been nice to see Battle of the Bands work in parties where two groups of people can go head-to-head on a agreed setlist and try to beat each others score but alas this works well for many of those who play RB often on Xbox Live.
RB2 has several new additions and features that keep the same gamplay fresh and new such as the Breakneck Speed Mode or the Drum Fill Trainer. However, even with all these nice features, it all comes down to the songs and RB2 arguably has a strong list of tracks to start with. If you have RB1 and a good number of downloaded tracks, you and your party can have hours of fun.
RB2 is a party game at its core and although the gameplay remains largely the same, the downloaded songs, mystery setlists and challenges make it a great game that can last well into year...that is of course until Rock Band 3 comes.