The art is insanely gorgeous. I really enjoy the premise and setting, and the intro cutscene is perfect. I love the vibe of the music, especially in the intro.
After about 20 minutes, gems have apparently stopped spawning entirely. The last several trips, I have wandered around until I ran out of fuel without seeing a single gem.
There doesn't seem to be any purpose to resting.
I agree with the others that food is way too scarce.
I also agree that the current navigation system of clicking on invisible markers is frustrating.
It is very unclear how to tell where I can advance to another area. I'll often get to the edge of an area expecting to get the prompt to move on, but instead get nothing.
While it's understandable for a demo, I think moving forward the most important thing should be giving the players more reason to explore the world.