planetarian ~the reverie of a little planet~ is a 2004 Visual Novel released for Windows PC by renowned Japanese developer Key. Orignally, released in 2004 between the company's larger works of CLANNAD and Little Busters, planetarian is unique among Key's various works in that it abandons the company's typical high school settings for a more fantastic post-apocalyptic world, and also in that it is a much shorter work that offers no choices to the player, instead simply presenting the story and characters through the visual novel format. It received an updated rerelease in 2006 that added full Japanese voice-acting to dialogue in the game, and was released with an English translation for iOS in 2014 and on PC in 2016.

planetarian tells the story of a nameless "Junker" in a post-apocalyptic world, struggling to survive in his destroyed world, scavenging for parts and necessities in the ruins of a particular city. The Junker is the player's lens into the storyline; despite the game offering no choices to the player, it adheres to the traditional visual novel format and the Junker is treated as a stand-in for the player. He is never named nor given an image, and his lines are left unvoiced so that the player can "insert" themselves into the his experiences. The Junker is portrayed as a rough, jaded individual, tempered by the hardhips of his world. However, during one of his expeditions into the city for scrap he can salvage, he encounters an abandoned planetarium and the singular working robot running the facility, a humanoid robot called Yumemi. Yumemi, oblivious to the destroyed world around her, is overjoyed to have a new visitor at her planetarium and welcomes the Junker with open arms. The Junker, unsure of how to react to this robot's behavior, still finds himself being inexplicably drawn into Yumemi's carefree, upbeat world. He helps Yumemi rebuild the planetarium's projector Jena and is moved by the world he sees, a world beyond the destroyed planet is now lives on. The Junker's hopes and ability to dream are restored by Yumemi's innocence, but the reality of the world continues to crash down on him, leaving the Junker to have to decide between the reality of the world around him or the dreams of a brighter world Yumemi gives him. (Yumemi means "Dreaming" in Japanese.)

While the overall storyline of planetarian is rather simplistic, the world is very fully realized and the characters are engaging. The simple scenario brings the emotions of the Junker to the forefront, both the highs of Yumemi's dreams and the lows of the world around him. The visuals are rather simplistic, being mostly made up of static images of Yumemi and static backgrounds, but serve their purpose well and are well-drawn. What brings the story together mostly strongly is the sound design, both in the voice acting and music. "Gentle Jena," the track that plays when the game starts up as well as during the turning point of the story of the Junker watching the planetarium's special projection, takes special mention for truly capturing the themes and emotions the story is presenting. Its hard to get through the visual novel without crying at least once, with the strong story, solid voice acting, superb music, and solid visuals coming together at key moments.

While the interactive aspects of this visual novel are limited, it doesn't diminish the power of the narrative presented within. Key uses their expertise with the format to tell yet another tearjerking, heartwarming story of hope, and the emotional power of the format is clear throughout. Key is often regarded as the masters of tearjerking visual novels, and planetarian is yet another example putting them at the top. While this work doesn't use the interactive nature of visual novels, the combination of text, music, and limited visuals tell just as engaging and immersive a storyline as any other medium. The limited visuals often work in the story's favor, allowing the reader to have a basis to visualize the events, but still leave gaps to fill in the details and become more emotionally invested. planetarian is a beautiful story of hope even in the midst of despair, and uses its medium to bring the emotional responses to strong crescendos.