How far can you fly and defend your world before it’s conquered. Conventional weapons won’t work. Specialized weaponry is ineffective. There is only one solution. Ram Jet. Use your Ram Jet to destroy all incoming UFOs by ramming into them. The more you kill the faster they will come. Every time you let one through the more your city will be destroyed. When your city is completely covered with the fire from another world the game is over. Watch for bonus items that will help.