In Portal 2, what color is the Repulsion Gel?

In Portal 2, Repulsion Gel is blue. It is one of the game's mobility gels, specialized substances that can be spread across surfaces to change how Chell and other objects move through the test chambers.

Repulsion Gel makes the player bounce, allowing Chell to leap unusually high when she lands on a coated surface. Puzzles use it to create spring-like platforms, redirect movement, and reach areas that ordinary jumping cannot access. The gel is associated with blue coloration, while Propulsion Gel is orange and increases a player's running speed. Conversion Gel, introduced later, is white and allows portals to be placed on otherwise unsuitable surfaces.

The gels are part of Aperture Science's long history of dangerous and impractical experimentation. Portal 2 presents them as advanced test materials, but Cave Johnson's recordings reveal that the company often developed technologies through reckless trial and error. A common mix-up is confusing Repulsion Gel with Propulsion Gel: blue means bouncing, whereas orange means speed. The two colors are designed to make their different gameplay effects easy to recognize.