It is recommended that you play the game here first before reading.
At first glance, Air Pressure seems like a fairly standard choose-your-own-adventure centered around your relationship with a girl named Leigh. The two of you have been together for several years now, and she’s been close to your side the entire time. This particular day is the anniversary of when the two of you first met, but it seems as if you are unsure about how things are turning out in your life. A part of you believes that you were happier before meeting her, but another part can’t imagine life without her. As you talk to her throughout your day, your choices determine how the relationship will continue. The next day, your relationship with her will either stay the same, get closer, or break apart. It seems like a simple relationship story, but then you notice something, something that appears to hint at a deeper meaning. In all three endings, she’ll start to appear “glitched”, with parts of her body flickering back and forth from existence. And in the “get closer” ending, you inevitably wake up in a hospital, with a nurse telling you that, “You’re lucky this time. You didn’t hit any nerves or arteries.” Clearly there is something more to this story than a simple relationship.
Many players, including myself, believe that Leigh is not an actual person, but the personification of some sort of pain. The type of pain, however, varies on the player. Some people believe she is the personification of an addiction to drugs. Others believe her to be the personification of self-mutilation or harm. There is plenty of evidence to support both theories. For example, the second line of the game states that “From the second we met, she wrapped herself around my left arm, and has stuck there ever since.” In the drug addiction theory, this would be a reference to the protagonist injecting his left arm with some sort of drug, and him continually doing so later on. In the self-mutilation theory, this would be a reference to a scar on his left arm caused from his first attempt. As the day progresses, many other hints are thrown around that could fit either theory. This includes the protagonist thinking his life was better before meeting her, his uncertainty surrounding whether or not he can survive without her, and his inability to be rid of her for good. But then there are clues that seem to only really fit one theory or the other.
One of these one-sided hints would be when the protagonist is talking to Leigh in town. He mentions that the noise of the crowd is giving him a headache. This by itself doesn’t mean much, but he only gets this headache when he is trying to get away from Leigh. If he tries to walk away, but eventually stops and talks to Leigh, he comments how his headache is going away. For the drug addiction theory, this makes a lot of sense. It can be interpreted that the protagonist is trying to get away from the addiction, and is experiencing withdrawal symptoms. Headaches are typically among the common symptoms for withdrawal sufferers. When he gets the drug again, he no longer experiences the withdrawal symptoms. For the self-mutilation theory, this headache doesn’t really fit.