Advanced Knee Replacement



The Advanced Knee Replacement is a device introduced in Portal. The device was created in order to keep Test Subjects from injuring themselves when falling from great heights. The Replacements protect the player from falling damage at any speed, even from terminal velocity. After. In Portal 2, they are replaced by the Long Fall Boots.

Trivia

 * The idea for the Advanced Knee Replacement was recycled from a cut character from Half-Life 2, the Combine Assassin.
 * The necessity to add the Advanced Knee Replacement came when Beta testers believed it unfair that the player could survive falls from heights that would kill you in most other FPS games, specifically Half-Life.