The package bit isn't being set for the plugin, and this means it acts as a regular old folder in the Finder, allowing the user to view all of its contents. Somebody needs to check their IDE's build target settings or makefile.
Also, the demo is pretty much useless if it will only process the top left corner of an image. I can see that it runs, but the preview pane is way too tiny for me to evaluate anything if it's not actually going to touch my image when I click the OK button. A time limited or watermarking demo would be infinitely more effective at convincing prospective customers in my opinion.