I wouldn’t normally even comment on an app when I haven't purchased the full version, and I'm sure the pro membership delivers a good product. But first, in a category that has such tough competition, it doesn't seem very friendly for the company to allow for a sample version that isn't essentially "complete" as a reduced-feature but satisfying app. This is fairly common. I can even respect the minimalist vibe: you're given a #2 pencil, a blue, ballpoint pen, an eraser and a doodle book to doodle in. It's straightforward and honest. But no color changes? Are we monks? The pencil is quite satisfying for what it is. It looks like graphite scribbling on rough paper. The ball point is not evocative of actual ball point, which can actually achieve quite a variety of line qualities. And if you're going to have the principled stance of such admirably few choices, you really ought to work out the glitches. At fist I could flip through the pages, but eventually couldn't go backwards. So drawings were lost, never to be seen again. Big no-no. The decision of whether to go pro was at that point, easily made. Sorry guys.