Kathy Rain is a 2D graphic adventure game with classic point-and-click mechanics. The game starts on 25th September 1995 when the protagonist Kathy Rain hears from her roommate that her grandfather Joseph has passed away. Reluctantly she returns to her hometown to attend the funeral and talks to her grandmother. Along the way it is revealed why Kathy's mother Shannon took her away, what happened to her father, and why she has not seen her grandmother for such a long time. Soon after Kathy left with her mother, a strange incident happened that left her grandfather in a vegetative coma. As Kathy is a journalism major she honours her granny's request to investigate the event. The people of Conwell Springs are not eager to bring back the past, especially when it turns out a suicidal young artist also took a secret to her grave. The game takes place over the course of five days.
The mouse is used to move Kathy around and interact with the environment. When one more than one action is available, different icons appear on a sign, such as 'examine', 'think about' or 'talk to'. Items are stored in an inventory where they can be combined or be used in the environment. Certain clues are added to a notebook, which are then used as starting points for dialogue options. Optionally the Space Bar can be held to display all interactable objects in the environment. Kathy cannot die and it is possible to save at any moment. Kathy rides a motorcycle and this is used to travel between the different locations. There are about 40 hand-drawn environments, a soundtrack and full voice acting.