The game follows the summer vacation of Boku, a city-dwelling nine-year-old boy who in August 1975 is sent to stay with his extended family in the Japanese countryside for a month.

Development of Boku no Natsuyasumi began in 1997, shortly after Ayabe left his position at the video game planning company K-Idea to establish Millennium Kitchen.

Boku no Natsuyasumi was praised upon its release for its visual style, nostalgic atmosphere, and art direction, though critics noted that its open-ended ambitions were hampered by the technical limitations of the PlayStation platform.

[3] Boku stays in the home of his paternal aunt Kaoru Sorano, her potter husband Yusaku, and their two daughters: fifteen-year-old Moe and eight-year-old Shirabe.

[4] Over the course his month-long vacation, Boku stays in a bedroom peculiarly already decorated with objects typical of a boys' room and maintains a picture diary documenting his various activities and exploits, the precise details of which vary depending on gameplay choices and story events undertaken by the player.

[8][9] Beyond the mandatory daily activities of morning radio calisthenics, breakfast, dinner, and bedtime, the game imposes no specific objectives or obligations of gameplay progression, and the player is free to spend their time as they see fit.

[7][9] Various activities can be undertaken by Boku, including but not limited to exploring the town and its surrounding environment, catching bugs, fishing, watering the Sorano family's morning glories, talking to the local townspeople, and flying a kite;[7] the player can alternately choose to do nothing at all.

[12] Ayabe initially approached Sony Computer Entertainment about publishing Boku no Natsuyasumi, pitching it as a game aimed at a target audience of adults in their 30s,[3][12] and stated that illustrator Mineko Ueda was interested in the project.

[8] Representatives from Millennium Kitchen undertook location scouting to gather reference material for the game in a variety of areas, including Tsukiyono, Chichibu, Saitama[12] and Mashiko, Tochigi.

[14] Ayabe additionally gathered photos for use as reference while visiting his childhood home in Hokkaido during his own summer vacations,[13] and was also the designer of the game's overworld map and buildings.

[8] The visual style of Boku no Natsuyasumi is distinguished by its use of cartoonish three-dimensional character models that are juxtaposed against backgrounds that are two-dimensional, pre-rendered, and hand-painted.

[16] Ueda's figures in both Boku no Natsuyasumi and her commercial work are characterized by their simple and cartoonish designs, with rounded features and dot eyes.

[8] A port of Boku no Natsuyasumi for smart devices was announced in 2016 at a press conference for the launch of Sony Interactive Entertainment's mobile games subsidiary ForwardWorks, but as of 2024 remains unproduced.

[27] Ayabe did not initially conceive of Boku no Natsuyasumi as a franchise, but found that advancements in technology across console generations allowed for enough interesting new gameplay possibilities to justify the development of sequels.

[20] [Boku no Natsuyasumi] re-opens a window on the nostalgia of a generation that grew up, but it does it with respect and generosity — there is no symbolic blowing of dust off of an old photo album, and there is no message about how great things 'used to be'.

[17] The game was widely covered in the Japanese press upon its release, including by NHK and TV Tokyo, with Ueda noting that mainstream outlets "treated [it] as a bit of a social phenomenon".

[9][29][f] Among the western press, critic Ray Barnholt wrote for Unwinnable that while the game is "not above" leaning on the tropes of Japanese summer vacation media such as "incessant cicada chirps, bug catching, fireflies, local summer festivals and a hell of a lot of sunflowers", he praises Boku no Natsuyasumi for telling "a kind of story that virtually no other commercial games have bothered to explore".

[32] Adesh Thapliyal of Polygon similarly cites Boku no Natsuyasumi alongside Animal Crossing, Harvest Moon, and Shenmue (1999) as "examples of the late-'90s turn toward daily life in Japanese game development".

[36] In a 2015 public survey by the Japanese search engine Goo to determine the greatest first generation PlayStation game, Boku no Natsuyasumi placed third, ranking behind Final Fantasy VII and the Resident Evil series.

[37] Subsequent to the release of Boku no Natsuyasumi, a glitch was discovered in the game wherein after certain inputs are made, the player will advance past the thirty-one in-game days of gameplay to "August 32nd" and beyond.

[38] As no story events were programmed for these days, the game becomes increasingly unstable with various gameplay and visual bugs, such as objects with distorted textures and character models with missing limbs.