Summer Days is an erotic visual novel developed by 0verflow, released on June 23, 2006, for Microsoft Windows and later ported as a DVD game and for the PlayStation Portable (PSP).

The game retains the anime-like presentation familiar to the franchise, requiring little interaction from users, engaging players through a nonlinear plot they are given opportunities to change, and concluding with an ending specific to the choices made during play.

In spite of the game's positive performance during this time however, Summer Days was almost universally panned for its heavily bugged state that prompted a disorganized release of large, frustrating patches and an eventual recall.

Each selection branches the game's progress up that point in an alternate direction, while also causing the player's love toward a character to blossom, plateau, or diminish,[1] thus providing for a nonlinear storytelling experience.

[1] Much like the other games in the franchise, Summer Days is unusual in that instead of traditionally static characters with subtitled dialogue,[3] it incorporates motion and voice, making it reminiscent of an animated series.

Cinamatics naturally play on their own, and players are afforded the ability to pause, fast-forward, and even skip those they've seen before; sex scenes, additionally, become unlockable from the main menu as they are reached in the game.

If the player is able to fend off their opponent long enough to fill their end of a progress bar, the game is won and a tally of how many times each key was pressed is recorded.

Though she finds the work almost thoroughly unpleasant, from the revealing uniforms to difficult customers, Setsuna manages to overcome the challenges of the job through the encouragement of friends, particularly that of Makoto Itōu, a classmate she likes.

The game focuses on the life of Setsuna Kiyoura, a character remembered for her impassive personality in School Days,[10][11] repurposed as the thoroughly more open and emotional protagonist of its sequel.

A first-year high school student out for summer vacation, Setsuna lives in the fictional city of Motehara[12][13] with her mother Mai,[11][14] a restaurateur who is frequently at work, and routinely visits Sekai Saionji, her childhood friend.

Besides reacquainting with Sekai's mother Youko, the owner,[11][16] and a couple of meddlesome co-workers, Noan and Oruha,[11][17][18] Setsuna meets a handful of new and familiar people on the job.

[11][24][25] Of the people Setsuna knows, Hikari Kuroda, a girl whose family owns a bakery known for its custard pie,[11][26] and Ai Yamagata, a bespectacled and soft-spoken classmate,[11][27] make occasional stopovers.

0verflow announced on April 26 that it would be attending Dream Party 2006, an anime convention, in Tokyo on May 4 and in Osaka on May 28,[29] selling retail copies of previous titles and Summer Days wall scrolls.

[33] On May 2,[30] 0verflow posted that the company would be visiting Akihabara, Osaka, Tokushima, Koriyama, Nagoya and Sapporo[34] showcasing the game and selling Summer Days phone cards.

[46] On June 28, having discovered that the game had been released in a heavily bugged condition, 0verflow issued an apology to its customers, stating that work on patches had begun and would be distributed to players through BitTorrent and retail outlets at no charge.

[54] As a result of the game's unprofitable recall, a rumor surfaced that 0verflow was forced to lay off half of its company employees, reported on at least once by New-akiba.com, a Chiyoda-based online magazine for Akihabara.

[59] Promotions continued with the attendance of Dream Party 2011 in Tokyo on October 3, where 0verflow sold brand phone cards and ornaments, T-shirts and dakimakura cases.

[78][79] The album contains all the game's background music, all of which was composed by KIRIKO/HIKO Sound, and theme songs performed by YURIA, yozuca*, Minami Kuribayashi and Kanako Itō, totaling 31 tracks.