Nope it is not hard. ~70 lines for ai and ~70 again for good movement.
Edit: @csganja
That is a bit to complex. You can just simply let the random make some coordinates within a given range and then just let the alien fly to that. Once it arrives just make new ones.
Edit: @csganja
That is a bit to complex. You can just simply let the random make some coordinates within a given range and then just let the alien fly to that. Once it arrives just make new ones.