That sucks, I'm sorry to hear that. I don't have a Mac myself, I had a friend try it out on his and it worked fine in Chrome, Firefox & Safari. Make sure you've got the latest updates first. Something you can try that might give me some kind of error-message is if you, in Firefox, right-click on the page and choose "Inspect Element". The page should split and show info on the right, at the bottom should be an error log. Reply with any error messages you have there and I'll see what I can figure out.
There aren't error messages, but lots of warning.
Maybe I found: Warning: Unsupported graphics API WebGL 2.0
So I can play the game, it runs, instead the images are hidden. Thank you anyway
I'm sorry to say that it might be that the graphics card on your machine doesn't work with WebGL 2.0. Could be the drivers but if they're up to date already there isn't much I can do to help you out sadly :(
Maybe try it out on someone elses mahine?