At first, I was a little bit thrown off by the mechanic of changing the color by moving your mouse. But then I realized its brilliance: it lets you compare different color schemes ridiculously fast. Very handy.
A bit of feedback: it seems that there is only two dimensions of changing the base color, corresponding with the two dimensions in which you can move your mouse. I can also see by the text overlay that saturation is locked in at 50%. It'd be nice if we had control over saturation. Maybe with a slider?
In the code mode, you can change the saturation with the mousewheel. For some reason, it changes the lightness in scheme mode. I'm not sure if it's intentional or a bug.
A bit of feedback: it seems that there is only two dimensions of changing the base color, corresponding with the two dimensions in which you can move your mouse. I can also see by the text overlay that saturation is locked in at 50%. It'd be nice if we had control over saturation. Maybe with a slider?