Pop & Hiss, the LA Times music blog, previews the game here.
Based on the preliminary preview I received recently at MTV Networks’ offices in Santa Monica, the game connects a deep respect for the quartet’s musical legacy with a sense of the inspired fun that was also central to their collective personality.
And here's an article which analyzes the game's Vocal Training mode.
Practice makes perfect, as they say, and if you want to five-star The Beatles’ songs, you’ll need to check out the Vocal Trainer in The Beatles: Rock Band. Ideally, to learn specific parts, you’d be able to isolate them -- but since The Beatles’ masters have all the vocals in one track, splitting up the stems wasn’t possible. That is, you can’t play back the Beatles’ individual vocal parts. Harmonix’s solution -- and a rather elegant one, at that -- was to overlay a “guide pitch” (in the form of the dulcet tones of a flute) on the vocals. You choose which one of the parts (lead, harmony 1, harmony 2) you want to be “highlighted” with the tone.