With all experimental settings on, it works for me in Safari for iPad (Pro 9.7, fully up to date). The sprite and room editor appear black until I press play, and then I can see the content after that. Sometimes it loads and just doesn’t work but if I refresh it generally starts working.
Colour palettes work super flakily and sometimes take multiple refreshes to show up, but that’s also the case for me on Chrome for OS X desktop, so! ¯\_(ツ)_/¯
I realise this is very ‘turn it off and on again’ of me but...have you tried refreshing a bunch?
Have also tried it in both Chrome and Dolphin for iOS but can’t get it working in either.