Portal Escape (Part 1)

This is the twenty-first level of the game, and takes place outside Test Chamber 19, in the rusty back stairways and maintenance tunnels of the Aperture Science facility. The player must utilise Flinging and precise portal placement in order to proceed.

Mechanics

 * Unstationary Scaffold
 * Flinging
 * Pneumatic Diversity Vent
 * Vital Apparatus Vent (dropper cover breaks and falls off when the player stands on it after the tube ride)
 * Heavy Duty Super-Colliding Super Button (H.D.S.C.S.B)

Hazards

 * Goo
 * Incinerator
 * Piston