"I can't imagine non-gamers getting confused by the act of running away from a linebacker"
I've heard this sort of comment a lot, which says to me that the people who say it don't often play games with girls.
The main thing that girls seem to struggle with in games is the movement system - particularly when the game requires you to move around in a slightly non-intuitive way (e.g. isometric viewpoint) while performing other complex tasks.
To generalise: if you hand a male his first ever controller and a copy of Halo, within one minute he'll be used to the movement axes (left-right, up-down, forward-back, strafe) and beginning to figure out how to combine them to get around; a female in the same situation will spend the first five minutes spinning in circles staring at the ceiling, or else standing virtually still and doing small, jerky turns without touching the "look" stick.
Sure, exceptions abound, and there are even more slick gamer girls than there are hopeless game-incompetent boys - but I'm sure the gist of the Halo example is familiar to most guys that have ever offered their non-gaming female friends a shot at a game in which movement involves the coordination of more than one input. It's the same principle as map-reading: males can usually imagine themselves on a map by rotating it in their mind to suit their orientation, whereas women can usually only imagine themselves on a map that's facing the same way they are.
I think the playing field levels out with practice, but a lot of girls try a game, find it too much work to get into and never go back.
I know I sound like a sexist prick saying all this, but I'm trying to point out the inherent sexism built into most games. It breaks my heart that my female friends should be locked out of so much fantastic entertainment simply because control schemes are designed for the male brain instead of the human brain.