Before anything else we are going to need to enable the developer console if it isn't already.

To do this we want to:

1. From the main menu select OPTIONS.
   
   
2. Select the Keyboard tab and choose the "Advanced" option near the bottom of the menu.
   
   
3. Tick "Enable Developer Console" and select Ok. Click apply at the bottom right of the menu and than Ok once more.
   
   
4. Ensure the console is working by pressing the tilde key. (The default keybinding) Proceed to the next section of the guide if your console is working.

Once you are loaded into any of the challenge maps (or advanced chambers) you can open your console with the tilde key ( ` ) and enter the command found below WITHOUT QUOTES. This will enable you to fly through the level straight to the exit. Simply do this and you will achieve a gold medal for that challenge once the exit elevator has closed.

"sv_cheats 1; noclip; sv_cheats 0"


Repeat this process for all 18 challenge maps and you will have obtained all three of the following achievements in one go:

Basic Science
Earn bronze medals on all Portal challenges.



Rocket Science
Earn silver medals on all Portal challenges.



Aperture Science
Earn gold medals on all Portal challenges.

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Additionally, if you are experiencing difficulty in completing the advanced chambers you can use the same method found above to obtain the following three achievements:

Cupcake
Beat two Portal advanced maps.



Fruitcake
Beat four Portal advanced maps.



Vanilla Crazy Cake
Beat all six Portal advanced maps.