In the first preview, the actor playing Brendan is in the bed on stage as the audience enters. As CarmenA3 noted, now the actor is hidden inside a dollhouse-like structure on stage, which is quite beautiful and must have been expensive to build. (Maybe they'll use it on Broadway.) But I felt sorry for the actor that now he has to be scrunched up for a half hour instead of lying comfortably in a bed. LOL
On Dec. 8, I was struck by the band's early rough patch, where they were jarringly out of tune and playing wrong notes. Eamon's mom comes in and talks to them about listening to one another. Then they start playing better. I don't remember that from the first preview, but maybe it's my bad memory.