The game includes an NES prototype of the game called "ROM City Rampage". It can be played within the Wii and PC/Steam releases, and also by using NES emulation software.
Created by a Grand Theft Auto fan named Brian Provinciano, Retro City Rampage was originally intended to be an 8-bit style remake of Grand Theft Auto 3. In 2005, the project, then known as "Grand Theftendo", was shelved. Four years later, the project resurfaced as "Retro Theftendo" and Brian started to add elements from other games he enjoyed in his childhood. He later decided to make it a full game with original content and thus the game it is today.