This wasn't a bad start to the game!
It would have been interesting to see the asteroid mechanic you mentioned and maybe adding a progression mechanic to the collection of ores (trading + upgrading) could add to the enjoyment as well.
One thing I would suggest is to perhaps add controller support as it might enhance the feel/control of the ship in addition to becoming more accessible for the disabled/motor impaired.
Overall I think this game is fairly enjoyable and has room to grow :D