Cool! I love the idea! There's nothing wrong with having a simple art style sometimes. :-)
It might be good to differentiate the colors of points and HP - at first I thought gaining points was HP since they were both green.
When I entered Sector 43 from 33, it said "I entered sector 33 for the first time".
Sometimes it said "Qirien has found a gem!" long after I found one, and I don't think there was another player with my same name...
I wasn't sure what to do after I got some gems - is there a way to bring them back to the surface? Maybe I should have asked the General more questions...