Hourglass of Summer is a visual novel that follows the protagonist, Kotaro Makimura, over the span of just over one summer. Just prior to summer break he runs into a suspicious girl who spills a strange power on him. From that night on, Kotaro finds himself awakening at a different time throughout the summer break. He quickly finds out that the girl he likes, Kaho Serizawa, will meet with an unfortunate accident that will result in her death before the summer's end. After gaining a handle on his situation, Kotaro must use this knowledge to prevent Kaho's death before his own disjointed timeline runs its course. Taking the role of Kotaro, the player must make decisions at key intervals that determine Kotaro's actions and his motivations behind those actions. As with most visual novels, everything inbetween plays out as if simply reading a novel on the screen with anime-style artwork and Japanese voice acting with optional English subtitles.
Hourglass of Summer (Natsuiro no Sunadokei in Japan) was developed by Princess Soft for the PlayStation 2, and later a PC release in Japan with added sexual content. In America it was one of the few titles to be released by Hirameki International Group in their "Animeplay DVD" line-up. These titles can be played on any standard DVD player or DVD-ROM, but have been criticized for their lack of flexibility compared to similar titles on the PC or standard consoles. There is no speed text-control, save functionality, or graphics view mode. "Saving" is handled by an old-fashioned password system which operates from scene to scene that feels outdated, but is at least functional.
Aside from format complaints, Hourglass of Summer was met with largely positive reviews from fans of the extremely niche American visual novel fanbase.