Review advanced portal locomotion techniques such as the Fling, Floor-to-Floor, Portal Ledge, Double Fling, and Wedge Fling in the Advanced Placement Portal Science section in Not Quite Rocket Science: A Portal Overview
Portals
Goal: Bronze Medal
Portal Limit: 23 or less.
Strategy: Use two portals to double-fling over the first Material Emancipation Grid. In the next room, use the bare minimum four portals to solve the first Catcher puzzle. You need three portals to get over the second grid when you go up the lift, and two more to get over the third grid. Solve the second Catcher puzzle with two portals, and use two more to get back over the grid. Use four portals to get into the final room, and four more solve final Catcher puzzle.
Goal: Silver Medal
Portal Limit: 21 or less.
Strategy: For a Silver Medal, follow the strategy provided for Bronze until you get to the last room. Here, instead of wasting portals to solve the Catcher puzzle, simply Floor-to-Floor to the exit lift.
Goal: Gold Medal
Portal Limit: 14 or less.
Strategy: For the Gold Medal, follow the Bronze Medal strategy until you reach the zigzagging passage with the poisonous goo. Instead of blowing six portals to traveling to and from the third grid to solve the Catcher puzzle, simply use the Portal Ledge technique until you can reach the second room. Use four portals to do this, and make sure that the last one you place goes on the ground beneath the exit lift. Use your last one to Floor-to-Floor onto the exit.
Steps
Goal: Bronze Medal
Steps Limit: 75 or less.
Strategy: You can easily achieve a Bronze Medal by using copious amounts of portals instead of walking, given all the portal-friendly surfaces in Test Chamber 15.
Goal: Silver Medal
Steps Limit: 65 or less.
Strategy: To shave off the ten steps required for a Silver Medal, double-fling at every opportunity. Otherwise, use portals in place of your feet.
Goal: Gold Medal
Steps Limit: 55 or less.
Strategy: The remaining ten steps can be eliminated by intrepid Double Flingers, and Floor-to-Floor travelers. Only walk when you have to, and when in doubt, use portals.
Time
Goal: Bronze Medal
Time Limit: 1:45 or less.
Strategy: Treat the first room as you normally would, albeit quickly. Same with the second room, but know that if the ball bounces more than once on the Catcher side, you’re in trouble. To shave off some time, don’t bother with the lift—teleport past it after it’s activated. Proceed as normal throughout the rest of the chamber, but be quick!
Goal: Silver Medal
Time Limit: 1:25 or less.
Strategy: Treat the first room as you did for the Bronze Medal, but you have to do the Catcher puzzle in the second room perfectly—not a single bounce on the Catcher side is acceptable. Teleport past the lift. Proceed as normal throughout the rest of the chamber, but in the last room, don’t bother solving the puzzle; instead, Floor-to-Floor onto the exit lift.
Goal: Gold Medal
Time Limit: 0:54 or less.
Strategy: Proceed as you did for the Silver Medal until you teleport past the lift after the second room. In the next room, teleport through the floor near the glass wall to the alcove, then double-fling across the grid. Use the Portal Ledge technique to get through the zigzagging hallway, making sure to leave your last portal on the ground near the exit lift. Floor-to-Floor onto the exit when you’re in the room.