A nag screen on some demo-ware is not really cool, especially if you don't give people a chance to buy the app or do something to stop the nagging.
The nagging will stop when the app is ready to be officially released. Until then, as you say, you can consider this "demo-ware" that is not meant to be left running. Consider yourself lucky that bigmuscle
was kind enough to give you a peek at the possibilities.
Remember, when bigmuscle
first proposed this project, he fully warned everyone that this was a work in process that was not ready for prime time. But everyone has acted like this is a ready-to-go commercial project and they are finding bugs and they are demanding they be fixed - as if it's his fault it doesn't work correctly on their system. If you are not prepared to try the software for a couple of hours and give bigmuscle
constructive feedback, then don't install it. Just wait until he officially releases it. At that point, and not until then, all the complaints of the inconveniences of popups and no installer will be legitimate ones.
Cheers and Regards