Cheat codes are codes that can be entered into a video game to change the game's behavior, alter characters' looks and abilities, skip levels, or access other hidden features. Trainer is a program written to intercept and alter the memory addresses of games that are running in the background. Usually trainers contain such features as GOD MODE, UNLIMITED LIVES and others that sometimes aren't pre-programmed into the game by its designers. Walkthrough is a document which attempts to teach a player how to beat or solve a particular game. Many people consider walkthroughs to be a form of cheating, but no game is suited to be a fair challenge to everyone.