Propulsion Gel

The Propulsion Gel is a testing element used in the Aperture Science Enrichment Center several centuries after Portal, and slated to appear in Portal 2.

Overview



 * Used as far as 1998 by Aperture Science, this orange and supposedly sweet and largely non-toxic liquid of fiberglass insulation was originally to serve as a diet aid, serving as a dietetic pudding substitute and marketed under the name "Propulsion Pudding". Its purpose was to increase the velocity of any food following it through the digestive tract, leaving the body no time to absorb calories. However it was pulled from shelves when it was discovered that digestion plays several crucial roles in the eating process, such as breaking food into manageable chunks before being violently expelled from the human body. The Propulsion Pudding was subsequently renamed "Propulsion Gel", and made for use with the ASHPD in Test Chambers instead, while another attempt at a dietetic pudding substitute, the Repulsion Gel, was tested.


 * As a testing element, the Propulsion Gel is to accelerate the velocity of any object it touches, giving them largely increased speed capabilities and allowing them to vault over pits or reach the far end of a long expanse quickly enough to best a ticking clock. Propulsion Gel is to be spilled through a vent, be dynamic, and play quite well with portals. Placing one portal under a vent and another in another area of the Test Chamber allows using the paint far from the vent, allowing to progress past a given obstacle.


 * "Repulsion Gel" is a registered trademark of Aperture Science.

Behind the scenes



 * The Propulsion and Repulsion Gels were first introduced as unnamed paint types in the April, 2010 issue of Game Informer. Gameplay footage and their proper name was revealed during E3 2010.


 * So far the expanded gameplay produced by Repulsion Gel and Propulsion Gel alone appears to be extremely satisfying, and Valve indicated a willingness to include more if it sees fit.


 * The Propulsion Gel mirrors directly the red paint featured in the student video game Tag: The Power of Paint, as the whole team was hired by Valve to develop it for Portal 2. The original Tag paint was developed by Pongthep Charnchaichujit.

Trivia

 * So far it is unknown why while the Propulsion Gel was already in use in 1998, it is not seen in the first Portal, set over 20 years later. However, it is likely that Chell simply did not venture into Test Chambers containing Propulsion Gel during this time.


 * The Propulsion and Repulsion Gels use the same colors as that of the ASHPD's portals (orange and blue, respectively).


 * While the animated diagrams of the Propulsion and Repulsion Gels show them to be contained in buckets, they have so far not been seen in any game footage.


 * When the player's sight is covered by Propulsion Gel, an effect similar to that of the Boomer bile from Left 4 Dead is used.

List of appearances

 * Portal 2