I just got Beatles Rock Band (not the full pack, just the game), and I'm enjoying it. Some songs are so unbelievably easy but others are deceptively, and impossibly, difficult. I play both the guitar and drums, but I'm at a Hard-Expert level on the guitar and a Medium-Hard level with the drums. Drums are way, way harder, IMO. It's the hand-foot syncopation that's the most difficult for me.

Are ALL of the songs available in one way or another? I was confused; I thought more would be included. I've unlocked one or two (haven't played it that much) but don't know how much more I can really unlock before I have to start downloading (paying for?) more of the gems.