Head’s up that Lesson 1.2.22 is missing the “Mark Complete” button.
Seems to have self-marked as complete when I got to the end of the video, but then had to select the 1.2.23 lesson using the right-col lesson listing.
(Viewing in Chrome on OSX)
This is strange. There is no functionality that would allow the Mark Complete button to be triggered once a video is complete. However, I know once a lesson is marked complete, it is not currently possible to mark it as uncomplete. Would that be functionality you want?
You should also have navigation options at the top of the page to move to next or previous lesson.