Game starts up, I click 'Login', it asks me if I want to update, I say 'Not Now' since this is my beta testing setup. The screen puts up the Mojang logo, then goes to full screen mode and puts up the dirt background.
Then a long pause...
Then a crash.
This is the same issue I experienced with 13W02a.
I just tried a completely clean installation, which I promptly upgraded to 13W02a, and had the same experience.