Alien level 11: Only way I found to beat it was to use the "+40% powerup duration" equipment and run the "invincible" route over and over. Best previous was 6 captures to their 10.
For mission 2/6 (defense), remember that you can repair the ship using the little drones so that you can slow your death with the 20 motherships. I finally beat it (on normal) by setting up a wall of lasers and THELS right about where the 20 ships warp in. Good luck! Remember to recycle anything you're not using to reclaim all materials...
In case anyone is wondering about the high scores: the game has been hacked. http://www.youtube.com/watch?v=d79pzrh8kDw Anything over 20K without cheating is very good.
This is indeed a great game. By the time you have a score of 25K, you probably know all the countries of Europe, Africa, and Central and South America like the back of your hand, and you'll remember them for a while too. When was the last time you learned that much from Kongregate :P
For point-scaling, note that there are three levels of closeness, not just two! Further than 220km, you get 1x score. Between 220km and 50km, you get 3x score, and closer than 50km (2-3 pixles) you get 5x score.
For all the "this is a TravelPod ripoff" comments — the idea of quizzing cities as a game is way older than Facebook. I'll grant that the way Globetrotter does it is very similar to TravelPod, but that's a smaller theft than the whole concept.
Just to put things in perspective, a score of 30000 means that you finish the game (75 cities) hitting one out of every two cities with the 5x point bonus (under 50km). The rest of the cities you must hit with the 3x bonus (under 220km). That's pretty damn impressive.