On the first level, go to the outhouse. Toss a stick of dynamite in it and blow it up. Go and look and you'll see the opening the dynamite made. Jump down it into the sewage and swim down. At the bottom is the opening to a secret area. Go through it, swim to the surface, and go down the tunnel. At the end is a strange colored cylinder. Go to the other side of it, open the little door in it, and look in to see the aliens.