Bad bad bad.

You will never get the output that you expect, or even what was previewed...
Has no concept of in-game resolution of the canvas, draws lines where there shouldn't be, draws over its own pixels (repainting, wasting time, ruining images).
"Dithering" ruins images, even if you prepare them yourself with the limited colors - and no way to turn it off.

App gets updates only when it breaks.