Choose your color according to the hue/saturation/brightness, a history of the last 6 colors can be picked and a nice selection of brightness variances is available.
The Brush tool has multiple options, you can paint behind the feather/writing ink, using simple brush, blurry brush or even watercolor.
You can adjust the size, the opacity, the thickness according to the speed and even the smoothness of the curve.
The Pencil give you a sketch texture, the more you scribble the darker it gets.
The size and opacity can be changed.
The Eraser tool let you rub out some part of your drawing, you can control the size, the opacity of it.
You can also use a blur filter to get a smooth erase gesture.
The Feather tool always paint over the brush painting.
It also has the same features as the brush, choice of the size, the opacity, the thickness according to the speed and even the smoothness of the curve.
Fill an area with the selected color in one touch.
Let you pick any color on the screen, gain time, paint fast.
The ink pen allow you to hand write, take notes, with a smooth ink design.
You can also control the thickness and the opacity of this tool.
The undo and redo let you go back and forth in the history of your action.
You can go back up to 10 steps in the history.