Wasteland 2: Director's Cut requires PulseAudio on Linux due to the requirement being baked into the version of the Unity 5 game engine we used for the game.
That said, according to some user reports we have received, it is possible to work around this requirement.
You will need to find all instances of libpulse-simple* and rename or remove the files. Places to check:
All of them must be renamed or removed.
Note: This work-around is unofficial and not supported, so it may cause audio issues or other problems or crashes with the game. We'd still recommend getting PulseAudio on your system if at all possible.