While I have exersized restraint and NOT gone in to preview anyone's submitted entries I know we have a good batch of demos already submitted (I peeked at the screen shots folks sent). I also see currently about 35 entries with no executable or images attached.
I suspect most people created a placeholder entry and will be uploading their executables as they complete their demos. When you go to submit, you attach your images and executable (or zipped package) by using the "add files" button above the text editor.
I'm looking forward to seeing all of the entries!