Ok, let me first state that this game is an absolute dream come true. My only disappointment has been in some of the charts. I know, I know, this game is meant to be accessible and try playing even relatively simple charts while doing either lead or harmony vocals, I know.
That being said, there are plenty of Beatles songs which are actually quite challenging to play, a prime example being "If I Needed Someone" If memory serves, it is a capo on 7th fret, and is played using a D7 chord position which changes with almost every note to either a regular D chord or some variation. The single notes in the chart just don't do this justice. Would have love to have seen a situation where your second and third finger play the same notes while your 4th and pinky finger are bouncing all over the place.
On a positive note - LOVED seeing the bass CHORDS in "While My Guitar..." Just like the real thing. Hopefully when Help! is released they'll hear those power chords too (conclusion of accapella verse).