Input seems to work fine (i.e. I can drag the paus where they should be rendered), but either render is not scaled, or the window is getting double the size.
Unfortunately, the most recent update has the same behaviour on my computer (see above specs)
the 'created' date of this build is May 4, while that of the ZIP is May 11. Perhaps you zipped the old build?
When I checked "Get Info" it is already in low-res mode, and that setting is mandatory.
On the old build clicking "run in low resolution" worked for me! For others reading this, you have to "get info" and the "low resolution" box is there.
Apparently I have a retina monitor but I couldn't tell from looking at the About This Mac!