First: I like the idea of mining here (first mine, then collect). Also the background is good.
Second: I don't like moving system, but I can used to it. "I don't like" doesn't mean it is bad. I just don't like. But I like the idea of flying and shooting at once.
Third, I have spotted a few bugs:
a. In update 0.4 you don't loose oxygen.
b. When you throw away inventory, save and open the game, inventory is lost.
c. Also when you completely close the window and reopen, most of the upgrades are lost. Plus you can't upgrade them once again.
d. I have reached depth of ~300 m and no silver, nor gold was spotted. I don't know if I should go deeper? I have plenty of other resources and I don't have any precious metals.