Portal/Chamber 19

Chamber 19 is the final test, after which you have been promised cake. "Welcome to the final test. When you are done, you will drop the device in the equipment recovery annex. Enrichment Center Regulations require both hands to be empty, before any cake..."

- GLaDOS

First room
The first thing you see in the room is a pellet launcher, a pellet receiver, and two platforms in a 45o angle to the floor (as seen in the overview image). The first thing that should be done is placing a portal below the pellet launcher. Remember not to create another portal, as the pellet would go through it. After this has been done, make ready to shoot at the other platform (timing is all important here). When the pellet is between the platform and the wall (as in the image on the right), make a portal below the pellet receiver. The pellet receiver then starts the moving platforms. Now, create a portal behind the stationary platform you can see, while looking down the hallway, and create another accessible portal.

Hallway
On the platform, you can see an appendix area farther down the hallway; create a portal here, and go through the one you just exited, so you are now in the appendix area. In this area there is a button, which opens the door next to you for a few seconds. Push this button, and create a portal on the other side of the door at approximately the same height as your current position. When a platform passes the portal, walk onto it (you do not have enough time to go through the door on a platform). In front of you there is a permanent pellet ricocheting between the window to the first room and the wall of the hallway. In order to deal with this, you have to create a portal on the wall, and when the pellet has gone through it, quickly create the other portal another place so the pellet does not ricochet back through the portal.

Now you are facing a wall, which you have to cross by creating a portal on that wall, and another on a higher ground on the other side, as shown in the picture to the left. When the platform reaches the wall, go into the portal, and jump back onto it when it has passed the wall. Remember that you are able to stand in the portal itself, without having the platform below you, so don't jump sooner than you should.

Oven
"Congratulations, the test is now over. All Aperture technologies remain safely operational up to 4000 degrees kelvin. Rest assured that there is absolutely no chance of a dangerous equipment malfunction prior to your victory candescence. Thank you for participating in this Aperture Science computer aided enrichment activity. Goodbye."

- GLaDOS

At this point you find out that the cake is, as prior wall-writings have indicated, a lie (or at least going through the fire is not the way to get it). Common sense should kick in (as well as some suspenseful music) and tell you that you should no longer listen to everything GLaDOS tells you. Therefore, you have to get to the platform above the oven. This is done by creating a portal on the wall behind the platform, and a portal on the wall to your side (slightly below your level, as seen in the image on the left). When this has been done, jump through the portal.

Do not worry about being chased by anything; you do not have to hurry to get out. On the platform, create a portal positioned as high as possible on the wall, and then one accessible to you. Go through the portal, and as you are falling to the ground, create a portal on the spot you will land on. Continue the only way you can into the next room.

Fourth room
As you try to go up the stairs, these will fall down. Create, instead, a portal on the second level and one on your level, and go through them. Or just jump onto the stairs. Go through the slightly open door by pressing your use button.

Fifth room
The next room appears to be something for turret building or repair. You have to get past a locked grid-door. Do this by creating a portal on the other side of it, and one on the wall, accessible to you.

Sixth room
Following the hallway, you come to a room with two fans blocking your advance. Create a portal on the other side of one of the fans and one on the floor in front of you. Go through the portal.

The room itself has a floor of acid, which you have to cross by creating a portal on the opposite walkway, and one on your side, as shown on the image. After this, create a portal in one of the upper corners of the opposite wall (as shown in the image), and one on a nearby wall, in order to jump to the walkway in the middle. You can explore the side office rooms if you wish, as they let you see some of the test chambers from the other side of those mysterious windows, but they do not help with the actual game. After this, go the other direction and into the next room.

Seventh room
Simply coming into this room, the next step is not obvious, however there’s a little picture in red indicating the portal placement necessary. Maybe the turret X drawer has been here too?

Get to one of the higher platforms (either will do, not much momentum is needed), by either walking or creating a portal there, and another one accessible to you. Then, create a portal in the upper far right corner of the wall. Let yourself fall, and create a portal on the spot you will land on. This way you will build up enough momentum to cross to the platform opposite to the wall.

"What are you doing? You haven't escaped, you know. You're not even going the right way... Hello? Is anyone there?"

- GLaDOS

Follow the hallway to the tube transporting cubes, and enter it.

Test area
At the end of the tube, you are put into a cube dispenser, from which you enter a very familiar test area. No cube this time, but on the other hand, you have both halves of the portal gun. In the test area, stand on the button in the middle of the room, and create a portal behind the door that opens. Then create an accessible portal, and walk through it. When walking farther, you get to the chamber lock, however this is malfunctional, and you have to jump down.

Chamber lock area
Now, create a portal on the underside of the platform on the other side of the grid-wall (as seen in the image), and then one under yourself. Then duck, in order to get into the room.

"Uh oh! Somebody cut the cake. I told them to wait for you, but they cut it anyway. There is still some left though, if you hurry back."

- GLaDOS

When you are in the room, go to the two pistons, which raise to two different levels. Go onto the one that raises the highest, and create a portal on the top of the platform you just entered through. Go back under the platform, create a portal there and use it to get on top of the platform. Walk onto the cylinder next to the platform, and let it push you to the platform to continue. Walk along the hallway, until you get to a grating. Create a portal on the other side of it, then go back to the platform to create a portal there, and walk through it.

Vent shaft
Create a portal as high as possible, opposite to the walkway leading away from the shaft. Then create one accessible to you. On the other side of the portal you have to jump in order to make it to the other side (the timing here can be rather hard).

No Cheating SpeedRun in One Segment for Mere Mortals
This chamber (and the rest of the game) does not have an associated time challenge, so the only reason to learn how to go through quickly is for a speedrun. Like the moving platform part of Chamber 15, it takes too long to get through the corridors the obvious way, so use peek-a-portal instead. Upon reaching the platform above the fire pit, there are no more opportunities for clever tricks and it is necessary to follow the normal path, executing quickly and perfectly. As always, practice until your best moves are in muscle memory.

As you step out of the chamberlock, place a portal at the other end of the corridor high on the left wall. Place the other portal under your feet as you step out and fall through, getting a boost towards the first room. Disregard the energy pellet mechanism and advance just until you can see around the corner and along the first section of the corridor above the toxic goo. Place the blue portal on a wall nearby and the orange portal on the far wall to the right of the fixed grating in the corner and somewhat below your present level. From this portal, you will need to be able to sight underneath the sliding partition that blocks the next section of corridor, but not be so low as to touch the toxic goo and take damage. Turning to the left, slide to the right through the blue portal until the glow around the portal changes to orange, but not far enough to fall out of the orange portal and into the goo. Shoot a new orange portal along the corridor to hit the far wall at about the same height, i.e. low, but clear of the goo, and immediately slide left to emerge from the blue portal before the orange portal moves. The corridors are quite long (longer than in Chamber 15), so there is plenty of time to pull this off. Repeat the exact same thing to bypass the next section of the corridor, keeping below the bouncing energy pellet. Repeat again, but this time take more care over the new orange portal placement. By keeping the portals low, you can again sight under the partition that blocks the corridor. This next one needs to be in a fairly tight area such that you will be able to sight over the platform above the fire pit but under the obstructing end wall of the goo corridor. Practice until you can find this spot reliably. After pulling back through the blue portal, you will be looking through the portals directly at the fire pit.

It is hard to judge how far to advance for a peek-a-portal when you're facing directly forwards, so again turn to the side and watch for the color change. Then turn forwards and shoot the orange portal at the back wall over the fire pit and pull straight back before it lands. Your view through the blue portal will change and you can step through onto the platform. You're now done with peek-a-portal in this chamber; the rest follows the normal walkthrough, optimized where possible and executed promptly and perfectly. Have your moves memorized, don't dally and practice, practice, practice.

As soon as you're on the platform over the fire pit, place a portal at the top of the wall behind you and the other under your feet. Fall and move the floor portal under you to fling over to the area with the large tanks. Turn to the left (in mid-air, don't waste time by waiting until you land) and head for the stairs. As soon as you have a sight-line to the wall over the walkway, place a portal up there (at the level of the walkway, otherwise you'll waste time falling), place the other portal in the wall nearby and walk through, turning left. Walk to the door, open it and go through.

In the next room (the "Fifth Room" listed in the Walkthrough, above), don't waste time portaling up to the walkway and then into the smaller room at the side. As soon as you come in through the door, place a portal on the wall of the side room, shooting behind the locked gate. To your left and to your right beyond the electrical box are portalable walls, so place the other portal and walk through. Swing left and open the next door. Without going through, shoot a portal towards the wall behind the large fan that you can see on the far side. It will probably be a matter of luck whether it lands on the wall or hits a fan blade, so back up, keeping your eye on it, and try again if necessary. You're backing up because placing the other portal on the wall to the left of the door is quicker than entering the room and walking forward until the floor is portalable.

When you're past the fan, turn to the right and shoot a portal along the wall and just under the suspended walkway to land on the far wall. You could put it high on the wall, but then you will be delayed by the fall. If you're keeping track of portal colors, now just go through the portal you're standing next to. Otherwise, if you've used the wrong color, you'll have to replace that portal. Once through, you're looking back towards the alcove into which you just came by going past the fan. There is a matching alcove and fan on the right hand side of the large room. Ignore the side rooms to your left and shoot a portal high on the wall above the right-hand fan alcove. Turn and jump through the other portal on the back wall to land on the suspended walkway. You're aiming for the part of the walkway that is wider than the center part so as to avoid over-shooting. Turn left and leave the room, passing a DANGER, ADMITTANCE TO AUTHORIZED PERSONNEL ONLY sign.

Turn to the right in the next room. Move to the left so that you can place a portal high on the wall that you are now facing. You need to shoot around the metal flooring that is bent down over your head and get the portal far enough to the right so that when you come out of it you will land on that strip of flooring. Advance to the edge, jump off and place the other portal on the floor under you. The jump is needed to ensure that the fling takes you far enough to reach the bent metal floor. Press and hold the move-forward key until you can see to the left around the next corner. The tube with the jagged hole in it is up on the higher level, but you can't see it. The obvious way up is to trudge around to the bottom of the stairs and walk up. It is quicker, however, if you place a portal as close as possible to directly over the tube, turn around, drop back down to the lower level (but not through a portal there) and place the other portal under your feet to drop gently through. Turn around to find the hole in the tube and go in.

After a ride in the tube, you will fall into a Vital Apparatus Vent (dispenser). Towards the end of the ride, look down, as this will give you the best chance of landing cleanly in the bottom of the vent so as to quickly trigger its opening. You will fall into Test Chamber 9. Immediately walk through the Emancipation Grid and towards the exit door. As you pass over the button and the door opens, place a portal on the wall behind it. Place the other portal on the floor just ahead of you and drop through. Turn at once to the right as you come out and go to where the chamberlock ought to be. But, there is no chamberlock, so just drop down the shaft. So that you are immediately ready to continue when you reach the bottom, turn through 180 degrees as you fall.

Place a portal on the underside of the horizontal structure that you see ahead of you, place the other portal under your feet and drop through, turning 90 degrees to your right and moving forward. You are facing a pair of shiny metal pistons. Wait until they come down and move forward again to stand on the second one. Turn 180 degrees to look back at the structure that you just portaled out of. When the piston rises, place a portal on top of that structure. Turn around, drop off of the piston and walk in an arc around to your left, threading your way between the shiny steel pillars and up a short set of steps. Continue turning left and you will see the horizontal structure again. Crouch and on the bottom surface, close to you, place the opposite portal to the one you have on top. Keep going until you are under that portal, stand up and jump up out of the top surface.

Turn to your left and you will see a long, shiny, steel piston traveling horizontally. If you have made good time, it should be drawing back. Jump onto it and turn towards the way it will travel. As it extends, go with it and jump onto the platform at the end. Quickly turn left, place a portal on the wall though the grill-covered opening that you will see and complete the left turn to jump back onto the piston before it starts to move again. It will draw you back towards the horizontal structure. Make sure that you have the opposite portal to the one you shot through the grill on top of this structure, jump onto it from the piston and go through. You will land in a narrow vertical shaft. Without turning, look up and place a portal as high as possible on the side facing you. Look back down, turning 90 degrees to your right and stepping back slightly, place the other portal there, move forwards and jump through. You should make it into an opening that was above your previous level. Go forwards and to your left to reach the end-of-level trigger.

From the opening of the entry chamberlock to the end-of-level trigger should be less than two minutes and twenty seconds.