Thank you for the feedback. I've never seen the last bug though, I will try to reproduce it.
Update: I tried to reproduce it on a couple of physical devices, but couldn't. I also tried to reproduce the bug on an emulator (Nexus 5X, Android 8.1.0, as you specified), but it was still all the same - the bug didn't show up. Could you describe what your actions were exactly when you reproduced the bug?

The lines are crisp because this is the only way to keep performance on a good level using native android Canvas. I could have made them absolutely smooth, but it would have hurt the performance when scrolling horizontally on a large time scale. Also, in support of the approach I used I can say that it's not very easy to spot these crispy points with the naked eye. However, one possible workaround for this issue could be enabling smooth points on a small scale (where there are little lines and little amount of drawings) and disabling it on a large scale (to keep performance on a good level).

Thank you for the screenshot, I decided to favor performance over little visual glitches. I described a possible workaround in my reply to Fair Dog.

Agree, didn't have time for this.

In a hurry I implemented stacked area chart as stacked percent based bars. I agree with this issue. But the y axis isn't completely wrong, it just doesn't have the 100 top value.

1. The navigation container doesn't have rounded corners because it affects performance, I haven't got time left to come up with a good solution. I could have just used empty left and right containers with rounded corners, but it would look weird. But the slider (both left and right parts) does have rounded corners.
2. Agree, didn't have time to polish the buttons animation. Left clipping looks weird. Plus, buttons are moved to new line when there's enough space in the current line.
3. I decided to stick with the recommended approach when changing themes, which is to recreate activity. On activity recreation I use android fade_in/fade_out animation, which uses duration equal to config_longAnimTime (500ms). This is why it might look slow. Anyway, animation duration could be easily changed with just one line of code :) Again, I barely had time for the main part, didn't even notice long animation time as an issue.
Thank you for the feedback!

Totally agree. Wanted to make dynamic number of items per row based on screen width, but ran out of time to finish it.

Agree