According to the developer, "This feature complete playable is about 6 weeks behind where I had wanted it to be but I can’t be too surprised considering the increased scope. We have been able to accomplish so much in so little time by our experience, fantastic team and tools."
This seems to indicate that the game will remain a 2013 release.
Meanwhile, Wasteland 2 will be at GamesCom 2013, but not as a playable demo. "We will be showing Wasteland 2 for the press, and discuss the game with them, so expect an influx of coverage following GamesCom," reported inExile. "We will not be showing the game to the public on the floor, but we do plan to create a video for our backers and fans, based on the area we’ll be demoing."
Wasteland 2 completed its funding back in April 2012, drawing $2.9M in funding from a proposed $800K.