[2] "Euphoria" is equivalent to Guitar Hero's Star Power, collected by successfully completing specific phrases in the song mix, called Perfect Regions, and can be released by pressing the Euphoria button, doubling the player's current multiplier as well as automatic crossfading when active.

[2] Activision had initially applied for a trademark on the name DJ Hero in early 2008, leading to speculation that Activision was making plans to compete against Konami's Beatmania series of music video games with their own DJ game as a possible spinoff of their popular Guitar Hero series.

[6][7] Activision CEO Bobby Kotick confirmed the existence of DJ Hero in an interview with CNBC on January 20, 2009, revealing a release "later this year".

[2] FreeStyleGames teamed up with London based music production company Crossfade Cartel owned by Ofei Sakyi and Dan Neil to ensure the overall quality of the soundtrack.

[10] Because of this nature, Neil stated that it was much easier to alter a mix to meet certain gameplay goals, taking only a few minutes to complete, compared with the development of songs for Guitar Hero.

[10] Neil stated they brought to artists and DJs working prototypes of the game and hardware to show them what the sampled music and final mixes sounded like, garnering interest from these groups.

DJ Shadow then proceeded to build off that to create the "wet version" with added effects that was used as the base for the gameplay's mixes.

[22] As part of the game's promotion, the DJ Hero controller appears in the music video for Kid Cudi's "Make Her Say".

Tim Riley, vice president of music affairs for Activision, stated that "We are deeply saddened by the loss of DJ AM.

[26] DJ Hero 2 was officially announced in June 2010 and was released in October 2010, featuring more than 70 mashups from over 85 artists.

Artists include Eminem, Daft Punk, Chamillionaire, Dr. Dre, Chemical Brothers, Kanye West, Metallica, Lady Gaga, and Rihanna, while Deadmau5, DJ Qbert, David Guetta and Tiësto are playable avatars in the game.

[30] Activision CEO Bobby Kotick stated that despite low sales of DJ Hero, they are committed to continuing the series, with the sequel due in 2010.

The gameplay is similar in nature to DJ Hero, where the stylus and touchscreen are used to mimic scratching and crossfading between songs.

The lawsuit contends that Activision purchased 7 Studios to both gain access to proprietary technology and to delay publication of the game so DJ Hero could come out first.

[34] The Los Angeles Superior Court in which the suit was filed did not grant the requested restraining order against Activision on DJ Hero.

[38] Over 100 individual songs based on master recordings were licensed by Activision, composed into 93 DJ mixes by both participating internationally known DJs and an in-house remix team.

[41] The individual songs themselves were pulled from a large number of music genres, including Pop, Grunge, Soul, R&B, Techno, Hip Hop, House, Drum & Bass.

[49][51][52] Reviewers also noted that there was a certain weight to the turntable portion of the controller which made scratching imprecise, particularly with the inner blue button where only minimal torque can be applied.

When progressing from "Medium" to "Hard" and "Expert" levels and encountering more complex mixes, reviewers thought the game felt transformed, bringing a difficult but more rewarding experience to the player as they begin emulating every part of a real DJ's motions.

[55] Richard Li of 1UP.com noted that the inability to fail a song is both "a bane and a boon"; newer players would not feel frustration at trying to get used to the controller and would be able to quickly unlock all the sets in the game's career mode, but without knowing where they failed, they would not have an idea of where they need to hone their skills to improve their performance at the game.

[48] The omission of a practice mode was noted by Daemon Hatfield of IGN, believing it would help in some of the more complex mixes by the DJ celebrities.

[55] Li noted a clear distinction in the quality of the mixes between the early sets—those mostly created in-house by FreeStyleGames—and the latter sets centered on the work of famous DJs.

[48] While Ben Kuchera of Ars Technica felt the soundtrack was good, he asserted that individual songs were unrecognizable because of modifications made to them for the mixes, and that they were more difficult to adjust to within the gameplay itself.

[52] The character designs of the non-celebrity avatars also continued to have the same Muppet-like appearances that occur in the Guitar Hero series, and are overly stereotyped.

[58] However, despite these figures, Activision claims that DJ Hero is the highest-grossing new intellectual property of 2009 in North America based on NPD data, which reporters attribute to the game's higher cost.

[68] Activision's Dan Amirch cited total North American sales of over 1.2 million units by June 2010, and commented on the "long tail" of sales that made DJ Hero initially appear to be a failure but instead has been considered a successful title by his company but they ran out of business.