60 Seconds Before Nuke - HECU Retreat from Black Mesa

Black Mesa was lost at the invasion of Xen and the cleanup of the Black Ops, so now HECU had to flee the facility and save their lives in the fastest way possible, due to the imminent threat of a nuclear device detonation. Nevertheless, their retreat was kicked and stomped by the invading Nihilanth armies and most of their efforts were smashed with great strength. Maybe Gordon Freeman’s actions would prove to save what was left of the military? Nevertheless the HECU were running out of vehicles and equipment, so they had to use whatever was left in their hangars and airfields, including captured Soviet tanks and helicopters which were the last resort of this crushing, flash war.