Sure, I can understand infinite rings, lives, time stops, character change codes. But adding an entirely new character, with separate controls- for a game that does not even reference those controls (port 2) such as this project for n64 - where Mario 64 became two player. (Purposely chose an older one, since I am not interested in all the fancy things done since then) Blows my mind. Are there any open source projects or places I can learn to do this? What technical skillsets are needed? Background in assembly? For a starter project I want to try achieving a similar state in a far simpler game like "102 Dalmatians: Puppies To The Rescue" in PS1. The reason I chose this game is because there are two models player 1 can access, and the game has a "bug" where sometimes a controller in Port 2 can control the AI fire rate. I figured this would be an easier target. I am familiar with Java, C, C++, Python but only barely touched the world of logic gates and assembly- but I am willing to dig into it. What resources would help me accomplish this goal? Edit: Source for the n64 hack: http://origami64.net/attachment.php?aid=252 ^ Clearly assembly, but what else do I need to dive into?