Update: I have uploaded a new version of the video, this time in OGV. Observations:
*The video now plays with acceptable performance in Firefox and the Wikipedia App on Android mobile
*The video doesn't play at all in the default Android browser, nor in Chrome on Android
*On desktop, the video doesn't automatically increase the quality of the file download when a user maximizes the window, meaning that a user who clicks the thumbnail on ENWP, gets the popup, then clicks maximize will likely see a file that looks awful when full-screened until and unless they find the button to increase the video quality.
*On IE on desktop, the default popup for me is for 360p even though that's smaller than it should be for the size of the popup that I get, so the video quality in the popup is poor. The popup should be for 480p.