I believe that’s referring tothe whole relationship between Otacon and Emma and Otacon and his stepmom in MGS2. The backstory where Otacon slept with his stepmom while he was a minor causing his dad to drown himself in the pool and probably the fact that his step sister was in love with him.
The Metal Gear Solid Collection is so true to Hideo Kojima's "original vision" that it needed a new content warning (www.gamesradar.com) angielski