Half-Life Havoc is a mod for Half-Life 2 centred around physics. The objective is to create a middle ground between Half-Life 2 and Garry's Mod. The idea is to take the constrained physics play present in Half-Life 2 and combine it with the lack of urgency present in Garry's Mod. You are presented with a number of premade physics games or puzzles, but each one is designed to encourage free play within the given puzzle. The mod makes use of Valve's developer commentary system so with developer commentary mode enabled you are able to hear explanations of the physics and the games. This allows you to experience the Half-Life 2 engine's physics system and explicitly consider the physics, rather than playing the game with the physics in the background.