Fight through connected Half-Life campaigns and a wide range of community maps with friends online or over LAN. Revive teammates, solve map-built puzzles, and keep your group moving together.
92%92% positive of 32,608 reviews297Playing now: 297Free
Trapped in a sinking submarine, two players must communicate through walkie-talkies to solve puzzles, complete tasks, navigate the depths, and escape before time runs out.