One possible theme could be confusion. Since it's not a fully - defined relationship, there would be a lot of uncertainty about where the relationship is going.
Possibly, the theme of change is in the 'half gf real story'. The relationship status can change over time, either evolving into a full - fledged romantic relationship or fading away into just a friendship. There could also be a theme of self - discovery. The individuals might discover new aspects of themselves through this unique relationship dynamic, such as their capacity for different levels of emotional attachment or their ability to handle ambiguous relationship situations.
One possible theme could be time management. Since it's focused on a day and a half, it might show how people make the most of a short period of time.
One possible theme could be survival. If it's about someone being in a difficult situation for a day and a half, like being lost in the wilderness, survival would be a major theme.
I'm not sure specifically what the 'half gf real story' is. It could be someone's personal experience about having a relationship that's not a full - fledged romantic relationship. Maybe it involves a friendship with some romantic undertones or a situation where the relationship is in a sort of limbo state.
One possible theme could be survival. Just like in Half - Life 2, the dog would have to face numerous threats and find ways to stay alive in a harsh environment.
One possible theme could be self - acceptance. If the girl has some sort of disfigurement or difference on half of her face, the story might be about her coming to terms with how she looks.
Another theme could be self - discovery. In a short period like a day and a half, a person might learn something new about themselves. For example, they could face a challenge during that time and realize their own strength or weakness.
One possible theme could be decay. Given the reference to 'half - life', which is often associated with the decay of substances in science, the story might explore how things break down or deteriorate over time, whether it's physical objects, relationships, or ideals.
The story might have themes related to self - discovery. In a short time frame of one day and a half, the characters could go through experiences that make them realize something new about themselves. Another theme could be about the unexpected. Because it's a short period, things that happen suddenly and change the course of the story could be emphasized, showing how life can be full of surprises even in a short time.
Another theme could be change. A half - moon is a stage in the moon's cycle, so the story may be about a character or situation in the middle of a change, like the transition from one state to another.
Suppose there's a group of friends, a girl and some guys. They often play games together. One day they start a 'cock - a - doodle - doo' competition. The 'gf' has to imitate the sound of a rooster better than the guys. She practices hard and comes up with a really creative and loud imitation. In the end, she wins the competition and they all have a great laugh about it.