People with apeirophobia really shouldn’t watch this.
Everything has been recorded at first-person perspective. It resulted in infinite psychedelic visuals such as giant spirals, never-ending walls, and gigantic perpetual portal rooms. Scary at first when you’re face to face with yourself. Such visuals potentially can trigger anxiety about mirrors and stairs to some people. There is no way to get out without restarting or using cvars. Chell doesn’t die by doing this, and it looks like there’s no gravity anymore.
For the record: Portals can move. In Chapter 5 (The Escape) at the thirty-third level of the game, you have to place portals onto moving panels to cut neurotoxin generator tubes by using a laser – This gameplay mechanism is not activated by default, so a special command was used to achieve the experiment.