Game mods are often created by fans of the game and are usually available for download for free.Ī game trainer, on the other hand, is a software program that modifies the behavior of a video game, typically by adding cheats or altering the way the game is played. Mods can range from small changes and tweaks to the game's mechanics or gameplay, to large-scale modifications that add entirely new content or features to the game. A game mod, short for 'modification,' is a modification or alteration to a video game that changes the game in some way.