Very cool site!
Vimeo embeds can be placed directly within the inner HTML of a rectangle. Embedding their embed code within an HTML widget results in a double iframe and that causes issues.
We'd be happy to look into this to see why this is happening. Are you setting opacity or display to hide the elements?
Another option is to create a blank scene which transitions to the next scene (either via crossfade or 'instant'ly) when the scene is loaded. This sets up elements in the DOM for scene one and two, and transitions to the next scene only after any preloading has completed.
This is exported if any of these are true:
- You are supporting IE 6-8 in the export process (only IE 6-8 loads this)
- You are using Physics
This post has more detail: Banner ad file optimization: What are full.min.js and thin.min.js for? - #3 by jonathan