[previewyoutube=jRi4AM8V_GI;leftthumb][/previewyoutube] If you still didn't understood how to play coop: 1. Being in start location do not start the game immideately 2. Press SHIFT+TAB to open Steam Overlay. 3. In Steam Friends find your friend and choose him to plat. Friend has to confirm invitation 4. Eait for automatical opening of a door and here he is! Right behind this door! And remember - both players has to be online - invisibility or absence of connection will not let you play togehther