Half-Life-Forget About Freeman!

The HECU determines that they are fighting a battle they cannot win against the Xen aliens; and having continually failed to neutralize Freeman, they abandon their mission and begin to evacuate the facility, calling in air strikes and heavy artillery to cover their retreat.
Gordon makes enters an underground storage garage to avoid the bombardments, and eventually fights his way through scores of aliens and several groups of the decimated HECU forces before reaching the Lambda Complex.