- Bronze: 12
- Silver: 9
- Gold: 6
6 Portal Strategy
- Proceed forward, drop the stacked cubes down one level.
- Shoot a blue portal at the center of floor directly underneath the pellet receiver.
- Drop down and kill both turrets.
- Stack a cube against the side wall near the button, climb up and aim an orange portal through the hole in the ceiling at the wall of that area.
- Facing the entrance, stack two cubes in front of the gap where a turret was then climb up to the blue portal.
- Carry a cube through the blue portal and use it to deflect the energy pellet through the portal and into the receiver.
- Place cubes on both buttons in the ceiling area then exit.
- Shoot an orange portal through the new opening and throw a cube into the blue portal.
- Duck and grab the other stacked cube and also throw it into the blue portal. At this point the one remaining cube should be on the lowest level but very near the gap where a turret once was.
- Carefully fall through the blue portal onto the metal platform. Drop both cubes off the ledge through the laser floor if they haven't already fallen.
- Jump across to the next lower platform and shoot an orange portal at the lower wall through the laser floor.
- Shoot a blue portal at the wall nearby, go through, and place a cube on the button if one hasn't already fallen there.
- Shoot an orange portal through the hole and carry a cube through the blue portal with you when the lightning has stopped.
- After placing the cube on the button, stand on it so that the cube placed by the gap earlier is reachable. Bring it down, stack it on the cube on the button, then climb and jump your way out.
- Crouch down to grab the last cube, place it on the last button, and proceed to the exit.