I got the room/overworld to be bigger than the camera and viewport and scroll to keep the player in the viewport.
It seems like the border values in "object following" don't quite work the way the docs say. If you set them to 0, the camera does not "immediately" follow the object. It seems to not follow it at all. But if you set them to a nonzero value, it will follow if the object moves within that distance of the edge of the viewport.
Still, I appreciate all the work it's doing for me.
I was also able to get an
html build going. (You can try it. All you can do is use the arrow keys to walk around.) It was fairly seamless, but I find it off-putting that you have to log into Opera to download the part of the IDE that does the web build. I guess it's for "metrics."