Total Annihilation: Core Contingency is the first expansion pack for the real-time strategy game Total Annihilation, developed and published by Cavedog Entertainment in 1998. The expansion adds 75 new units, 25 new missions, and six new world types, along with additional multiplayer maps. It builds on the core mechanics of the original, which featured 3D-rendered units and terrain, resource management based on metal and energy, and a vast tech tree. Core Contingency does not alter the fundamental gameplay but significantly expands the available content. The new worlds introduce varied terrain and environmental hazards, such as acid oceans that damage ships and crystal landscapes that favor air units. The new unit roster is distributed across land, sea, and air, with a particular emphasis on naval additions. The most notable new unit is the Core Krogoth, a towering assault robot that dwarfs the Commander unit. The expansion was generally well-received for its volume of new content and for maintaining the balance and feel of the original game.