It runs fine on my gentoo. I'm using alsa, not pulseaudio, but I think ubuntu uses pulse by default, so that's not much help.
Bear in mind that when you run godot from the command line, its default is to run whatever project is in the current directory. It might have trouble if there's an empty project there (or it thinks there is). If you run it as "<godot> -e", it will try to open the editor for the project in the current directory.
