If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Alien Intruders is a one of the best online alien game. In this cool game you control a space ship and your aim is to destroy a team of space invaders. The invaders will shoot you back in return and will approach closer and closer. There are special enemies, once destroyed, they will give you some very nice weapons. Use your weapon in order to win in this terrific game. Good luck!
Use arrow keys to move ship left and right, use space for shooting.