Hey, look, I made a video! I couldn't resist because I was enjoying watching my little truck drive around so much. It's just adorable.
A new feature in Moon Invaders 2 is that the aliens now fight back. So one part of your strategy has to revolve around how you defend yourself. Luckily, your towers can't actually be destroyed, they just shut down (in the video, they don't, they keep on shooting when 'dead') and await repairs. The repair truck drives back and forth fixing any downed towers. So you'll be able to upgrade the health of your towers, build shield towers to cover them, upgrade your repair truck, add more trucks, EMP enemies to prevent them from shooting, and so on. A whole new world of strategery.