1) Character development in short films focuses on establishing a character's current wants and philosophical beliefs due to limited time for backstory. This allows the audience to engage with what is at stake for the character.
2) Storylines in short films are kept simple and focused on a single idea/theme due to short length. Visual storytelling is essential to convey information with limited time for dialogue.
3) Short films still require narrative structure with characters overcoming obstacles to achieve goals, creating stakes, even with limited length. This keeps the audience engaged in the story.