Mars Madness

You have been stranded on Mars! Sadly your weapons have been destroyed, but you still have a mining gun and an amazing mind for engineering. By holding left-click on a piece of ore you can mine it. You can then press "I" to open your build menu where you can transform your ore into Gun Turrets or Mines. Mines will extract ore if placed near a lump of ore. Turrets will shoot the incoming enemy. The aliens come in waves, the wave timer is in the top right.