Nintendo DS

DS was a video game console that Rani Chandra owned in 2009. Rani was not a big gamer and used the console for "casual games". Amongst the games that she owned were a "cute cooking simulator", an "very unrealistic law simulator", and a game about looking after pets. (PROSE: The Last Sontaran)

Real world

The Nintendo DS system was released by Nintendo in 2004, although the console in the novel is never referred to as a Nintendo console, simply being called the DS.

Rani's games are references to actual Nintendo DS games, all released prior to 2008:

• The cute cooking simulator" is likely referencing Cooking Mama, a cookery simulation-styled minigame compilation developed by Cooking Mama Limited. 
• The "unrealistic law simulator" is a reference to Ace Attorney is a serious of legal thrillers visual novel games, developed by Capcom.  
• The game game about looking after pets is likely Nintendogs a real-time pet simulation game developed by Nintendo.