Z Chamber 00/01 Developer Commentary
Developer commentary may include spoilers; I recommend you finish PortalZ before reading further.
Hello, and welcome to the PortalZ human-written commentary center. In lieu of a proper in-game commentary mode, I have typed up some comments here related to the development of PortalZ. This is a project I have been working on (with quite a few breaks, obviously) since 2009 or so. It has gone through quite a few changes since then, influenced by other map packs, mods, Portal 2, and my improving skills as a level builder.
It starts in my take on the relaxation vault. As you can see, this is a bit friendlier than the original. This was intentional—a lot of this map pack came from the idea of an alternate universe in which GLaDOS was benevolent and did not lie to you, and I started giving that impression with a larger and better-furnished relaxation vault.
I stressed a little about continuity with only the bed being on a panel rather than the entire vault, but years later, Rexaura did the same thing, so a least I am not alone.
When I was new to mapping, throwing in a G-Man cameo seemed like fun. Later, it felt a bit cringey, but since Portal: Prelude had several, keeping just one seemed OK. I also put way too much effort into making it so if you look at him and look away, he might disappear. That was mostly difficult because the game engine can tell whether you are looking at him directly, but not whether you can see him through a portal; hopefully I didn't miss any spots where you could see him disappear.
As with Portal's first room, this room forces to see yourself walk through the first portal. In addition, the delay here forces you to wait and makes it more likely that you will see the emancipation grill that GLaDOS is talking about. Finally, there is a spike pit. I decided to use spike pits until goo pits are formally introduced because spikes are more widely recognized as dangerous.
I generally assumed people would play this after completing Portal, so building a series of tutorial levels would have been too much, but I liked the idea of building a playable version of the first Portal trailer to quickly (re)introduce Aperture signage and the portalgun. For players who have not played map packs with blue walls (or Portal 2's hard light bridges), they still have something new to see during this part. I decided to stay with the Combine force field wall texture because it would easily be recognized by players of Half-Life 2 or the Portal: The Flash Version map pack, and most PC players would not have played Portal: Still Alive, where they look more like what would become hard light bridges.
I actually had a little trouble with this room. The cube did not want to stay still on the sloped platform, but it had to be sloped enough that the portal device could hit it and the player could see the portal get created. The cube actually has to be held in place with a small invisible wall until the portal is created.
In recreating this part of the Portal trailer, this chamber introduces the idea of dropping an object through a portal from a distance, which the player is not forced to do very early in the original Portal test sequence.
This room continued the goal of quick refresher of puzzle elements before players get started without a whole series of tutorial levels. The infinite loop fling was a bit difficult to pull off, and ended up needed a bunch of invisible walls to make sure the cube lands on the button.
On the other side of this wall was a behind-the-scenes area in which the player would get the HEV suit. I had to give the player the HEV suit because I wanted xem to be able to sprint, since I found Portal's walking speed a bit tedious. (Spoiler alert) You also need it to be able to switch weapons, which becomes important at the end of the map pack. This was in the map pack for a long time, and I even worked on an alternate Aperture Hazard Suit texture for it and a more extensive Portal story I had worked on. Unfortunately, it was difficult to communicate to the player why xe was being pulled into this BTS area, and it got cut in favor of the player having the HEV suit from the start. I couldn't bring myself to delete it entirely, though, so you can still use cheats to go through the wall and visit it.
I hated waiting for elevators in Portal, so for the longest time, test chambers were just connected to each other by identical hallways with level loads in their middles. When it released, Portal 2 presented a solution: have elevators that get shot through vital apparatus vents. That was not only a good way to do fast elevators, but also removed any need to question how all the chambers are laid out relative to each other in the facility.
I finally created these elevators with the 2020 update. While they look similar to Portal 2's at first glance, I actually spent a lot of time iterating on the design so they felt at home with Portal 1's art style. Like Portal 2, however, you will always arrive in the next chamber facing the elevator doors, primarily to minimize waiting, but also so I did not have to rotate chamber entrances and exits to line up.