[2] Early screening for the first episode was held in March 2008 in Tokyo Dome City and Osaka Mido Hall.

[4] The third episode was partly leaked four days before its intended air date due to human error.

[21][22] In anticipation for the DVD volume release, Madman streamed the episodes on a weekly basis beginning on October 27, 2009.

[24] The opening and ending themes for the first 12 episodes are "O2" (O2〜オー･ツー〜, Ō Tsū) and "Shiawase Neiro" (シアワセネイロ, lit.

[12][80] The picture drama (ピクチャードラマ, Pikuchā Dorama) episodes are still images and character voices used to tell a story.

In the United Kingdom, Kazé announced its acquisition of the series during the London MCM Expo in October 2012.

[114] They released the series as a DVD and Blu-ray box collection on March 11, 2013, with distribution by Manga Entertainment.

[19][20] In Australasia, Madman Entertainment released a single volume, then concluded with a DVD box collection on December 20, 2010.