Assassin's Creed Unity may be taking some lumps from critics, but—not kidding— gamers need to appreciate how good the game's kissing is. Don't snicker.
Video games have a tough enough time animating individual characters and tougher times animating the interactions between two. Even at that, they can do violent interactions between bodies fairly well, but they struggle with subtler actions like, say, a kiss. Often, games cut away when characters kiss or cut to a camera angle that occuldes the character's mouths.