Half-Life-Endgame (Both Endings & Credits)

When Gordon comes to his senses, he finds himself in front of the G-Man. Both are transported to various locales around Xen, while the G-Man praises Gordon's actions in the borderworld, to later explain that his "employers" have agreed that Gordon has "limitless potential," and have authorized him to offer Freeman a job.
The G-Man and Gordon are teleported a last time to the same tramcar he rode on the day of the incident, but now flying through space at immense speed. By stepping into a portal, and knowing that his only other choice is a battle he has no chance of winning, Gordon accept or decline the G-Man's offer.
If he accepts,he enters the portal and finds himself floating in nothingness.He hears the G-Man's voice one last time; "Wisely done, Mr. Freeman, I will see you up ahead..."