Nice!

I've never heard of isolating the green channel of the normal map and using it as a paint layer. What effect does that create exactly?

WARNING They dont listen to their users as much as they like to say they do. Check their forums. Plenty of requests go unanswered. Their "To Do" list has been outdated. They lack staple features such as a Text Tool, Adjustment Layers, Channels, Layer Styling, Proper Cropping. Paintstorm cant even resize a photo correctly (It will always leave a border when resizes). You also run into square artifacts occasionally. There have also been several instances were paintstorm was detected as malware, once called out, the dev reuploads a clean version. This happened at least twice from forum reports and Virus Total. Aside from the very obvious lack of support and maintinence. The brush system is good. However a good brush engine will not replace the other basic features and functions paintstorm lacks. DO NOT expect support. This is definitely a homegrown app and it shows. If you want a versatile brush engine, clip studio or even krita is where its at.