Turn off Buffer Paint Window and Sequence Tracking in Preferences in the File menu. For slower cycling try values in the range of 4-8 ticks or so. Longer intervals make for a stop motion or stepped feel for another effect. Turn on Ignore Outside Apps in the Bliss menu. Sound input can also be used to trigger Bliss Paint's color synthesizer.
Volume is mapped onto one of the color oscillators.
Options can be controlled in the Configure Sound dialog of Bliss Paint. There is an Octopus mode with many different Bliss Paint features mapped to MIDI controller messages. Bliss Paint 2.0 has much more access to the parameters of many of Bliss Paint's features, painting algorithms, and more. Yes, although Bliss Paint must be in the foreground to do the animation, so the other application must run in the background. The color cycling and rendering is really slow on the second monitor on my Power Macintosh 8500.