The Advanced Chambers, on the other hand, are unlocked from the start. The 20 chambers unlock in order you need to beat Still Alive 1 to get to Still Alive 2, and so on. This was mentioned in the story page, but a video of it will be provided lower on the page. The three categories are time, steps, and portals used, and the easiest one to get a gold medal on is Test Chamber 14's portals used category since it's super easy to finish in only two portals.
Another achievement requires you to earn at least one gold medal on any of these 20 maps, or one of the original Test Chambers 13-18. For three more achievements, you'll have to complete these at least once. There are 14 new chambers added to this version of Portal, and there are also six advanced chambers, which are enhanced versions of Test Chambers 13-18.
