How to play the commentary tracks?

[bricktop]

Love the game so far. I got to the part where the floor is flooded (same place as in the demo). I enabled commentary tracks in the settings menu. Now I see the commentary nodes in the game. When I touch them, they start spinning but no commentary tracks are playing. There is also a ",,,," or "...." under the node if I hover the cursor over them. Restarted the game and still the same problem.

Is it because i haven't completed the whole game or is this some kind of a bug?

Bought the game from Frictional store and activated on Steam.
(Win7x64, Core2 e8400, 4GB with a Creative X-Fi soundcard).