Lua scripting has been used in game development for decades, and many games, including Critical Ops, use Lua as a scripting language. Lua scripts are used to create custom game logic, AI, and user interfaces, and are typically executed on the client-side (i.e., on the player's computer). GameGuardian, on the other hand, is a tool that allows users to modify game memory, enabling them to manipulate game data and create custom scripts.