Same problem here, it is unusable right now, even with medium sized brushes (standard round) and at screen size of an ipad 12,9 inch :C

Heya, I bought Paintstorm long ago in 2016 and wanted to start using it more now, but it is completely unusable at the moment, am I doing something wrong? I have an iPad Pro (first Gen), work on relatively small images (2000x2000px with 150dpi) and even standard brushes lag extremely. Just a soft ro...