If I let the game take up one monitor, then click a different program in another, either
(a) in fullscreen mode, the game window minimizes and both monitors temporarily blank out or
(b) outside of fullscreen, the audio cuts out.
I understand that multi-monitor support may not be a priority, but I think one of the strengths of this style of game is how compatible it is with multitasking.
This is in Windows 8.1 preview, not sure about other versions.