Homesick tells the story about a man who is searching his past and identity. The player takes the role of the unnamed man, who is exploring an abandoned apartment complex. The gameplay is based on solving puzzles and exploration shown from a first-person perspective. The story unfolds by reading letters and books, and watching old photos from the former inhabitants.
The gameplay is divided into two parts. At daytime you can explore the environment, but must avoid sunlight because of the protagonist's light sensitivity. At night you are able to reach other parts of the building complex during your nightmares.