Great feedback, thank you. Some of your criticisms are due to there being no explicit tutorial. For instance, there is a purpose to resting, which is actually linked to the spawning gems. But those things will come more into focus down the line.
Your last point about giving players more reason to explore is absolutely correct. This demo is very low on content and is missing at least three specific mechanics that the final version will have. We'll have a solid update coming in the next month that will address those issues first and foremost.
Thanks again for taking the time to share your thoughts!