Would it be easy to implement disks 1 and/or 3 if they were released?[/quote]
</div> Laughably easy.
So laughably easy that here's a patch with the three cart games all embedded in the ROM portion of the disk. It's a better demo really, and then you can copy them to use as a base for your own stuff.
<a class="externalLink" href="http://www.mediafire.com/download/0mg1nui1fhc4eb0/DezaPelican.7z" rel="nofollow" target="_blank">http://www.mediafire.com/download/0mg1nui1fhc4eb0/DezaPelican.7z</a>
Now with preview!
<iframe allowfullscreen="" frameborder="0" height="300" src="https://www.youtube.com/embed/lQudJR-0YRg?wmode=opaque" width="500"></iframe>
Heck, the contents of <i>all</i> of them could be inserted into a single image because of the way the thing works. For that matter, any generated content can be hardcoded back in.
Point of interest: looked into the goofy nature of the disk 1 and disk 2 content and how some (maybe all) of the common images don't seem to function right. The references are to the wrong image source file, yet if you compare them to one of the other image files present they would have lined up. Just a guess, but these disks were probably made against older versions of the game during development. From the looks of the video, disk 3 is probably the only one designed for this final version.
Unless I'm mistaken, disk 3's text file is named "MESSAGE.EXE" internally. It should be able to run other kinds of code too.