At the end of the each episode, you have to eliminate
the most powerful alien in the game. You will find her in the
egg chute. This is where she is best left. First, use any gun
to take care of the eggs and facehuggers. Once the eggs are destroyed,
shoot the Queen's chute to bring her down. The battle requires
a lot of ammunition. Use the heavy weaponry such as the pulse
rifle and smartguns. She will eventually die and you can move
on to the next level.