Left 4 Dead is a cooperative first-person shooter developed by Valve and released in 2008, built around four Survivors fighting through campaigns filled with Infected. Its audio design became a big part of its identity, with short cues signalling danger, special enemies and sudden turns in a run. As clips from the game were ripped and shared on soundboards and in video edits, those brief sounds took on a second life outside matches. This one survives because it instantly signals horror-game pressure, even for viewers who have never played a campaign.