The graph-dragging interface is very difficult for me to use on mobile (Firefox on Android; most of the times I tried to grab a point to move it up or down, it just added a new point between two existing ones and moved that instead. I definitely can understand that it's hard to make an interface to allow a user to draw an arbitrary curve, but I feel like this could be solved by just limiting the granularity of the points the user can select further; I really don't feel like the experience is improved by being able to select eight or so different points that all have to fit horizontally on the right half of my phone screen.
Had the same issue trying to "move points I had placed" but that doesn't seem to be how it was designed. Moving from left to right, drawing the line in one continuous motion worked great.
Correcting a guess means drawing over from any point moving right.
The interface seemed really well done even for mobile. Tested it on chrome and Firefox for Android. I'm Really impressed. NY times does some great interactive and visualization work.
It works great on desktop. Relies on the mouse, of course, which is problematic when so many people are browsing on mobile. I understand the desire to have high quality interactive sites, but when half your readers can only use their thumbs...
