Hey guys!
If you don't own this game yet (or if you want another copy for whatever reason^^), What Lies Beneath is now available on the Flying RPG Bundle.
http://www.flyingbundle.com/
Also, I just released a beta version of the co-op update (which will let you play the singleplayer campaign with a friend). More infos on that topic here : http://steamcommunity.com/app/333330/discussions/0/611703999969543195/