Similar situation for myself. Have just updated C2 to export to the arcade. After the update I went to check if the project was still working.
Neither the preview worked, nor when I exported the file and uploaded it to my site.
http://englishacorn.com/html5/Test/Simple_Menu/index.html (Tested on FF, IE and Chrome, the first layout begins with a black opaque layer which fades away. This was working prior to the lastest update)