Games have been growing progressively more cinematic, working in scenes that could belong in a Hollywood blockbuster. But technical limitations still get in the way of otherwise simple tasks, as Assassin's Creed 4: Black Flag lead writer Darby McDevitt has discovered.

"What's easy in cinema is sometimes the complete opposite of what's easy in a video game," McDevitt told GameSpot. "So, for instance, if I said I wanted a shot of 15 people sitting around being drunk, that seems so easy to shoot in the cinema: you just get 15 guys; they all act drunk; done. In a video game, if all those were unique characters, it would be impossible because you'd run out of memory. You couldn't display 15 unique characters all on the screen at once."

Even without large memory-eating crowds, a simple moment of emotion can be so specialized that it's difficult to animate. "I'm always bewildered when I'm writing a script and I show it to the cinematics team and I go, 'It's just a guy. He starts crying, and a single tear rolls down his cheek.' And they're like, 'Darby, that's gonna take eight weeks to make! We can't make single tears!' You always have to be careful what you ask for."

As a result, the writers and designers go through their plans on a daily basis to make sure they line up. The cutscenes, which McDevitt helms, have to serve some gameplay function of setting objectives. In an action-oriented game like Assassin's Creed, that means the action needs are usually at the fore. "It's almost as if you were writing a movie, but you were writing it with the fight choreographers. It's like Jackie Chan writing a movie with his fight choreographers, you know? That would be a super-fun movie."