Broken Age has long blown past its originally projected release date, but the documentary series available to backers continues to be a regular and excellent thing. Each episode goes into the development process in great detail - and in doing so, telegraphs news like this long in advance: Act 2 of the adventure game has slipped from the end of the year and into early next.
A post on the Double Fine forum says that the team has grown, playtesting feedback has been positive, but that they "just gotta give the game the time it needs" to get it finished. The new timeline means they're aiming to hit alpha on the project before the end of the year, and the game is apparently "well on it's way towards Beta", which is the stage at which Kickstarter backers can help with testing.
There's also good news for those who found the Act 1 short, as that playtimes during testing of Act 2 "have ranged from 8-12 hours". That's at least double the playtime of Act 1, if John's experience are any measure.
Double Fine Adventure was one of the earliest games to hit it big on Kickstarter and the project ballooned in the wake of its success. That partly accounts for why it long ago missed the estimated delivery date of October 2012. The other reason - as made clear through the now hours-long documentary series - is that the design of the game has been 'felt out' as development has gone along. Iteration is a great way to make games better, but not necessarily a great way to hit deadlines or manage projects. It's terrifying and fascinating to watch Tim Schafer and the Double Fine team walk a tightrope while at the same time braiding the rope only a step in front of them. Even if you don't care about the game, watch the episodes whenever you can.