With no real improvements to the series, Lego Rock Band's sole purpose is to serve as an (inconsistent) track pack
Cons: But the style wears thin quickly; Some really poor choices in the tracklist; Really odd content restriction system; The game is really just an expansion pack of Rock Band 2
I'm gonna be honest right up front: if you're getting this game, it's so you can export the tracks to another, better, Rock Band. Perhaps you want some Jimi Hendrix (who made his debut in this game surprisingly), or maybe you're a fan of the Final Countdown. Maybe you're like me and instantly wanted Song 2, A-Punk, and Breakout. Or of course there's always the Ghostbusters Theme.
Regardless of which specific songs, if you're interested in this game, there're likely a small handful of songs you really want. Odds are you haven't heard of the songs in the rest of the game. And I'll tell you now that you still won't care about most of them when all is said and done-this collection of songs shirks the series' golden standard for more contemporary, poppy (read: generic, annoying, and often boring) songs. It's a shame, because it's an unfortunate burden to have to suffer through so much filler for the game's best songs (which are legitimately great on the level of past Rock Band classics).
That's all the summary you should need for the game, but if you decide to actually play the game, maybe for some achievement points, or because you think Legos are cute, then you'll find it's identical to Rock Band 2. As with that game, notes scroll down the screen (or across if you're a vocalist) and you must hit the right notes in time with the song. Lego Rock Band makes attempts to appeal to a younger demographic by adding a Super Easy mode that eliminates even more of the challenge, but otherwise is identical to other Rock Band games.
The other chief difference is the art style. As you might expect in a Lego game, the little yellow people are everywhere. Already less serious than the other Rock Band entries, this difference is capitalized with humorous cutscenes in the game's story modes and the awesome Rock Power challenges. Throughout the game's campaign mode (which, by the way, is a linear version of Rock Band 2's campaign mode), certain songs are used to complete objectives such as destroying a building, fleeing a robot T-Rex, or surviving a giant octopus. These portions play identical to the rest of the game, but the little stories playing in the background are always interesting.
That said, the low production values for the rest of the art style wear thin quickly. It may seem cute to have Legos playing all these songs initially, but when you realize that they aren't synched with the same level of detail as other Rock Band entries, it just feels off. This only gets worse when you have Lego versions of celebrities that have very little resemblance to their real counterparts. Luckily, in a game about staring at a note track, the background graphics have little bearing on how good or bad the gameplay experience is, and the game remains fun.
As said, the reason to get Lego Rock Band is so that you can export the gems to a superior Rock Band game. This isn't a bad game by any means-after all, it shares the same base as the rest of the series-but it's hard to recommend compared to the superior track list of Rock Band 2 (and now its sequel). The game might have been better released as DLC singles, because in the all-or-nothing package on-disc, it's a bit harder of a sell. What you get out of this game varies with your taste in music, so instead of recommending or not recommending the game like I usually would, I'm going to suggest that you give the track list a spin and see if it is worth having in your collection instead.