Aperture Tag: The Paint Gun Testing Initiative

Aperture Tag: The Paint Gun Testing Initiative is a Portal 2 modification featuring gameplay focussing around the use and manipulation of the Gels featured in Portal 2.

Story
The events take place after the events of Portal 2's cooperative campaign's Mobility Gels course, and before the events of the Art Therapy course, in the Aperture Science Facility, while GLaDOS had finished building the Aperture Science Paint Gun. A test subject wakes up in an Aperture Science Extended Relaxation Center's restroom ready to begin their test. They are introduced to Nigel, a personality core and his test associate. He then is put through a series of tests featuring the Aperture Science Paint Gun, Aperture Science's final product. When the testing is over, Nigel was surprised that there was someone to complete every single test chamber and thinks that he is the proper one to deactivate the old Aperture Laboratories stability Stable Energy Reactor (ALSER), the energy supply of Aperture Science, as a new one was built. Nigel is very surprised that he made it through so easily and decides to put him through another round of tests.

Mechanics

 * Aperture Science Paint Gun
 * Allows the player to coat a surface with a never-ending supply of either Repulsion Gel or Propulsion Gel, and allows the player to pick up objects in a similar fashion to the Handheld Portal Device.


 * Aperture Science Paint Gun Activation Field
 * Has two sides: The green one activates the Paint Gun so that it can shoot gel, and the purple one deactivates it.


 * Aperture Science Vacuum Delivery System
 * As a substitute to Portal's Chamberlocks, the Pneumatic Diversity Vents are used for transportation between test chambers.


 * Glass
 * Much like non-portalable surfaces, you can't put Gels on glass.

Nigel
Nigel is the Core that helps you in Aperture Tag. He looks like the Space Core from Portal 2 but is in fact a reskin of the Fact Core (also from Portal 2), with an orange eye instead of pink.

Heavy Metal Core
An easter egg found in a test chamber, the Heavy Metal Core sits in his chair and listens to a heavy metal version of Still Alive and bounces his eye container plate up and down. His eye is alternating red and white bands.