Version 0.2.1 fixes a pretty minor bug that was reported on itch.io where the 1px brush would begin behaving oddly after you resized the brush.
It turns out that the problem was that the app was passing around brush size as a string rather than a number, so some of the behavior to reset the brush position / size wasn't working correctly. I'm surprised that the app worked as well as it did with that problem.
With this, I think I've fixed all the bugs that I am currently aware of. If you find any more, as always please let me know either via github or itch.io's comments. I do also appreciate feature requests; while I cannot guarantee that I'll add any feature in a reasonable amount of time, I do like seeing how people use the app and what they want to see.