This is great. Simple idea that is effectively executed. I'm such a fan of limited or non-dialogue films in this comp as it really forces your focus. Same goes for not having music and only diegetic sound. Loved the literally pendulum we were seeing and hearing. The eerie nature of the visuals raised lots of good questions too in my head about what was happening. Didn't notice the sound issue and have watched it three times! My only slight criticism is I found the camera panning a little jarring - a smoother back and forth would have given it a more organic feel and motion.
One of my personal favourites; rewatchable and recommendable!