Explain gain behaviour on Samsung sensor

Using Megapixels preview and the gain slider, analog gain seems to blend 2 kinds of gain.

0-~60 goes from reddish to dark, 60-max goes from dark to colorful.

At the 0 extreme, there's quite interesting behaviour with what would be overexposed at max retaining detail, resulting in a high dynamic range. This could have something to do with the sensor, but it could also be due to the color matrix supplied to Megapixels.