Within the game you are presented with a caricature of Mongrel Mob member Greco, from the Notorious chapter in the South Island.
The caricature is made up of an image of Greco taken by a New Zealand artist, who has asked the Herald not to be named.
The artist did not want to be associated with the app, or media coverage of it, and had contacted those behind the game to get the image taken down or legal action would be launched.
The caricature is superimposed to include the gang member wearing an iconic Mongrel Mob T-shirt and red Crocs, as well as holding two pistols.
Greco stands outside a dilapidated building which serves as the Mighty Mongrel Mob gang pad.
When the game begins, a Black Power caricature enters from the right and left of the screen - also wearing a Black Power T-shirt and blue Crocs - and carrying knives.
The aim of the game is to shoot the Black Power member before he gets close enough to stab the Greco.
If you are too slow, and the Black Power member gets close enough to Greco, he launches into a stabbing frenzy with blood splatters and swearing included.
User reviews have appraised the game as a "great quality game" and "the funniest thing I've seen on here".
One user said, "I loved the realism in this game it's just like being on the streets in my hood."
While another said, "Love the dynamics and quality of this app. Every part of my body has been stuck in an orgasmic trance since I got to finally fulfill my lifetime goal of being a Mighty Mongrel."
The game is rated for players 12-years-old and up and states that it includes moderate violence and mild swearing.
Greco, from the Mongrel Mob Notorious chapter, died in 2012 with his tangi held in Flaxmere, Hawke's Bay.
