Like another reviewer(s) said, this is NOT a painting app. This is an app that simulates Japanese brush calligraphy (墨絵, "sumi-e")—and does so quite brilliantly. Traditional calligraphy uses only black ink with a brush or brush pen, as well as red ink for the artists stamp or signature. With the addition of red/contrasting ink in this version, it does this perfectly.
As a long-time user of version 1, I am happy to purchase version 2 and continue using it. It is ideal for practicing my Japanese penmanship, and I occasionally prefer to draw in it instead of more powerful drawing apps like Procreate and Pixelmator, simply because of its simplicity and Zen-ish focus.
If you appreciate the aesthetic of an extremely-well designed brush engine, the simple beauty of one color with a contrasting one, and a multitude of traditional (and non-traditional) backgrounds, then fall in live with Zen Brush 2. If youre looking for a full-featured painting app, grab Pixelmator or Procreate. Then come back for Zen Brush 2 when youre ready for something with ideal simplicity.