The best two-player co-op games are built especially for two, or include a full collaborative experience, rather than a tacked-on multiplayer option to a primarily single-player game. Sometimes you want to experience a game from start to finish with a friend, enjoying the highs and lows of puzzle solving, combat, or exploration, and working toward a shared outcome. While drop-in co-op is plenty of fun on its own–check out some of our best couch co-op games for plenty of recommendations…