gradient brushes.
This application also has tons of keyboarding shortcuts (some of which will be familiar to Photoshop users) to make the maneuvering of this application even more comfortable. The fact that it does have very limited possibilities, to its advantage is the time needed to learn all of the important shortcuts.
FireAlpaca is a great alternative image editor, because it is extremely light and easy to use, and on top of that it comes with the sufficient quality to edit almost any image.