Chamber 18

Portals

Goal: Bronze Medal

Portal Limit : 30 or less.

Strategy: Use two portals to get across the first chasm, two more to get up to the next ledge, and two more again to reach the one after that. Use two portals (one of which has to be on the floor of the nearby lower platform) to fling to the button. Use four portals to solve the Ball Catcher puzzle, and five portals to neutralize the turrets. Use three portals to fling to the Cube, and two more portals to get back behind the protruding wedge. Use two more portals to get to the open door, and six portals to Floor-to-Floor to the exit.

Goal: Silver Medal

Portal Limit : 25 or less.

Strategy: Use two portals to double-fling across the first gap. While in the air, place one portal on the floor on the next ledge, as in advanced mode. Use one portal to get up to the next ledge, and one portal to reach the one after that (since you already have one on the floor). Use two portals (one of which must be on the floor of the nearby lower platform) to fling to the button. Use four portals to knock over three of the turrets, and three portals to solve the Ball Catcher puzzle. Use three more portals to fling to the Cube, and two to get back behind the wedge. Jump to the open door, and use six portals to Floor-to-Floor to the exit.

Goal: Gold Medal

Portal Limit: 16 or less.

Strategy: Use two portals to double-fling across the first gap. While in the air, place one portal on the floor on the next ledge, as in advanced mode. Use one portal to get up to the next ledge, and one more directly above the one already on the floor. Drop through and in midair place one portal on the floor of the next ledge and Floor-to-Floor onto the button platform. After entering the large chamber, place one portal on the wedge and one portal on the lower platform to fling to the Cube. Use two portals to get back behind the wedge. Jump to the open door, and use six portals to fling to the exit.

Steps

Goal: Bronze Medal

Steps Limit: 150 or less.

Strategy: You should be able to achieve the Bronze Medal simply by playing through normally and being frugal about your steps.

Goal: Silver Medal

Steps Limit: 120 or less.

Strategy: You should be able to achieve the Bronze Medal simply by playing through normally and being frugal about your steps. Be efficient about portal usage by ensuring that you place them near ledges you’ll need to drop from whenever possible.

Goal: Gold Medal

Steps Limit: 85 or less.

Strategy: To save yourself the last dozen or so steps, you’ll have to wedge-fling into the room containing the Cube when you first enter the large chamber with the turrets and rotating Ball Launcher. Yes, this means you can’t activate the Catcher, or kill the turrets.

Time

Goal: Bronze Medal

Time Limit: 2:10 or less.

Strategy: You should be able to finish the challenge in under the allotted time without any special considerations.

Goal: Silver Medal

Time Limit: 2:00 or less.

Strategy: To shave off some extra time for the Silver Medal, don’t bother killing all the turrets in the chamber with the elevated platforms.

Goal: Gold Medal

Time Limit: 1:12 or less.

Strategy: To shave the last 50 seconds off your run through, you’ll have to wedge-fling into the room containing the Cube when you first enter the large chamber with the turrets and rotating Ball Launcher. Yes, this means you can’t activate the Catcher, or kill the turrets.