Half-Life-Questionable Ethics

Gordon eventually winds up in a secret part of the facility where he discovers that scientists had been "collecting" specimens from Xen since long before the incident occurred.
Inside, Freeman continues to rearm himself to rejoin the battle against the HECU. He also meets the alien military units, the Alien Grunts; and finds one of the most powerful weapons in the facility, the Tau Cannon. Soon, he heads outside to search for the Lambda Complex.