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- Gold: 12
12 Portal Strategy
- Proceed forward, shoot a blue portal through the blue energy ceiling onto the wall of that area.
- Shoot an orange portal on the wall near you then grab the cube.
- Shoot a blue portal anywhere on the "X" marked ceiling, drop through with the cube, and kill or leave the sentry.
- Carry the cube with you on the moving platform and use it to deflect bullets from the sentry above.
- Press the button, this will start the energy orb emitter and kill the upper sentry. Deflect the second orb into the receiver by holding the cube at a 45 degree angle to its path.
- Duck and carry the cube through the small tunnel the energy orb just passed through then drop down with it.
- Shoot an orange portal on the wall near the cube then drop down and kill the sentry.
- Shoot a blue portal on the wall near the sliding door, grab the cube, then place it on the button in this room.
- Shoot an orange portal through the sliding door onto the opposite wall.
- Step halfway through the blue portal, shoot an orange portal onto the opposite wall as far to the left as possible, then quickly go back through the blue portal before the new orange one lands.
- At this point the cube may be brought along or left. Bringing it may be slightly easier towards the end.
- Step through the blue portal then quickly peek around the corner to the right, shoot a blue portal as far to the right on the opposite wall as possible (only if you are taking the cube with you- otherwise a shot anywhere on the wall will do), then quickly step backward to recover health from the sentries shots.
- Step through and jump to the small alcove. From here, shoot an orange portal as far to the right as possible on the opposite wall.
- Quickly step partway through the blue portal, shoot an orange at the opposite wall, then fall back through the blue portal before it lands. This will allow you to grab the cube and carry it through.
- Step onto the moving platform, then face backwards with the cube to deflect bullets. If it wasn't brought with then quickly slide into the first alcove and kill the sentry, wait for the platform, then slide into the second alcove and carry the sentry along with you to the next room- preferably alive. It is also possible to grab the sentries as you pass, but you have to be very quick. Further, the first sentry can be left alone completely as long as you are hugging the wall closest to the sentries.
- In the next room place the cube or the sentry in the right hand corner facing the alcove with the button.
- Jump on top of it and fire an orange portal as far to the left as possible on the wall at the end of the hall.
- Fire a blue portal at the corner of the wall in front of you as close as possible to the floor and portal immune wall.
- From as far away as possible, press the button then jump through the blue portal towards the timed doorway and to the exit. Jumping backward may help, but if you carried the cube all the way to this point it is much easier to run forward with it and quickly jam it in the doorway so that the door can't close all the way. Then just duck under and head to the exit. If getting to the entrance even with the cube is too hard, set it next to the door before pushing the button.