Ive always used this app for quick and intuitive editing on the go, and there are few things I have against the app. However, they are there, and I hope these things can be fixed/implemented in the future. First, a bug: Im not sure exactly how to reproduce it, but I believe it has something to do with the app refreshing after letting it run in the background for even short periods of time. The app seems to clear its undo history prematurely, so if I switch to Safari or another app to look at a reference, answer a text, etc. I cant undo any strokes upon switching back. Next, suggestions. Steady stroke tool. As convenient as this app is for sketches and slight retouching, I think porting the steady stroke functionality from the desktop version would greatly broaden its uses. Its fairly difficult to draw accurately with your fingers, so it seems like common sense (and no great expense) to include this. Blur and sharpen tools. I understand if mobile operating systems cant handle this though; my MacBook Pro can hardly handle them with any more than one layer. (Im writing about my experience with iPhones 4s-6s)