why not it would be nice to save ur progress
Because it's it's actually quite short (you can complete it and see all the content there is to see in about an hour) and devs did not see it as necessary at the time? Unfortunately, as explained in store description, the provided proof of concept demo is all there is and will be as the student group that made is no longer together and there is not going to be further development. Kinda shame as concept is solid.