Nebulaz.io is a space shooter with a top-down view. As in many other similar games you get more ships that are added to your armada once you collect enough resources. What's different about this one is that you have to mine a certain combination of the 3 differently colored minerals and actually purchase the next spaceship yourself.
The shooting is completely autonomous: your ships will automatically attack the closest opponents. All you have to worry about is directing your fleet with your mouse and buying new ships.
If you enjoy this type of gameplay, you should definitely give Nebulaz.io a try.