CSS SCI FI 3: Hardwired is a single-player modification for Half-Life 2. Waking up to find himself an augmented clone of Gordon Freeman, the player must fight time-travelling Combine forces and other enemies across 42 unique and replayable missions.

Missions are set in 18 retail and 24 custom Counter-Strike: Source maps, which are installed intact to the player's CS:S game folder. The mod edits the entity data for each map as it is loaded, adding and modifying entities to create a seamless single-player experience. The maps remain unchanged and are fully playable in Counter-Strike: Source. Maps have been contributed by established designers, including Bluestrike, Schuzak and d00ds.com. Combat locations range from a snow-covered country church to a dense pine forest to a sun-baked tropical island.

Players enter each map through the mission hub and can choose to play each one at a time or all in 3 linked campaigns. Each mission features a series of goals, such as to rescue hostages or destroy targets, which must be completed to move on to the next map or return to the hub. There are multiple approaches to each goal, and in each map the behaviour and armament of enemies and the distribution of resources are randomly determined within defined parameters. Thus, no two plays are the same, making CSS SCI FI a truly replayable single-player experience.