I'll copy and paste this from Heilo's old AvP1 walkthrough:
Final battle with the Queen. Your bullets have no effect on her what so ever.
Flame and Grenades stun her. She will attack by throwing boxes or by slashing
you. This level is difficult. You have to do a button hunt. First. run out and
hit the button for the Airlock panel. There's nothing you can do with the other
two buttons right there though. Next, draw the Queen over near the pile of
missiles. Shoot it when she's near to cause them to explode, knocking her down
and stunning her. (Unfortunately this pile is not here on Director's Cut, so
you cannot stun her with it or use it to blow up the grate. Just shoot the
grate.) Drop down the broken grating and run to the left. There's a button on
the wall. Push it and wait for the panel to open, the shoot the two pipes
inside. Turn around and run to the stairs on the right. Shoot the grating
above them and climb out. Go back and hit both buttons on the Airlock panel.
Turn and run back to the emergency cell on the right. push the button next to
the door and let the door close (sometimes you may have to hit it twice). This
will pull the Queen and everything else out of the room. Victory. Not bad for
a private. Missing this emergency cell will cause YOU to fly out. Not good for
a private. Congratulation, you've beaten the Marine game. Shame you're reading
this... Now onto the bonus levels!
