Rockstar Research

Rockstar consists of:
Rockstar Japan from 2005–present - Japanese localization studio, in which they work in conjunction with Capcom
Rockstar Leeds from 2004–present - Previously known as Mobius Entertainment and based in Lower Wortley, Leeds. They created Grand Theft Auto: Liberty City Stories and Vice City Stories for the PlayStation Portable, Max Payne for the Game Boy Advance and recently finished developing Grand Theft Auto: Chinatown Wars and the music game Beaterator.
Rockstar Lincoln from 1999–present - Quality assurance and localization studio based in Lincoln, England, previously known as Tarantula Studios.
Rockstar London from 2005–present - Formed in November 2005. Took over development of Manhunt 2 after Rockstar Vienna had been closed and recently developed the portable adaptation of Midnight Club: Los Angeles.
Rockstar New England from 2008–present - Acquired on April 4, 2008, this studio is based in Andover, Massachusetts and was previously known as Mad Doc Software. They developed the Xbox 360 and PC ports of Bully.[3]
Rockstar North from 1999–present - Creators of GTA
Rockstar San Diego from 2003–present - Previously known as Angel Studios, they developed the RAGE engine, Red Dead Revolver and Red Dead Redemption, the Smuggler's Run series, the first two Midtown Madness games and the Midnight Club series.
Rockstar Toronto from 1999–present Take Two's in-house development team, previously known as Rockstar Canada. Their most well-known work is their adaptation of the cult classic film The Warriors and the PC and PS3 port of GTA: Episodes from Liberty City.
Rockstar Vancouver from 2002–present Previously known as Barking Dog Studios, they created the PlayStation 2 title Bully and are currently developing the third game in the Max Payne series, Max Payne 3.
Rockstar Vienna from 2003–2006 Previously known as Neo Software; closed on May 11, 2006.[4] They ported the Max Payne series to consoles, and created most of Manhunt 2 before being closed down.

All information taken from wikipedia.org

As seen the majority of Rockstars games have been for an older audience.