I see you added a button (thanks!), but that doesn't solve the information problem where the person won't know why it isn't working and that they need to click the button. I suggest a simple highlighted message right above or below the image. Your "holds the first frame for anyone who prefers reduced motion" blurb is _buried_, and in my case I didn't even know that I had that enabled.
Is it mobile only? I'm on a mac, it doesn't work in chrome / safari / firefox - no js errors, no apparent 404s or missing resources, all the pages load, the ascii art is first black and white then colors appear quickly but no animation. It's a shame because it looks beautiful on mobile.
