While I am excited to hear that a major book publisher is interested in writing for games, there are several things I feel Random House would need to address as it moves some of its book authors over to the wilderness of game writing:
Thing the 1st:
There are two types of games: those that tell a story of which the player is but a small part of, and those that tell a story of the player's character from their perspective. I think the most egregious game design errors is when someone chooses to make a game in a genre that supports one type of game, and then attempts to tell a story the other way.
Half-Life 2 and Portal are exceptional at telling a story about a character, from the character's perspective, and leaving enough room for the player to feel like they are adding some of their personality to the characters of Chell or to Gordon Freeman. Sure, other things happen completely outside of their control, but never does the game put its foot down and say, "You want to make this decision because that's what Gordon Freeman wants to do". The player is never ripped out of Gordon's head and forced to watch him make a decision without the players input.
On the other side, you have games like Monkey Island, or Tales of Phantasia, Gears of War, or just about any other game where the player-character can talk. Having the player-character speak is not an immediate detraction in immersion, you just can't put this in a game where you want the player to feel like they "are" the character they're playing. I mean, what would happen if there was an extended ending cutscene in Portal where Chell goes and robs a convenience store to celebrate her new-found freedom from Aperture? It would kill the immersion because the writer has taken away the decision-making control from the player in a game where the player was given that decision-making control from the very beginning.
So, figure out what type of game you're writing for before deciding how much freedom you're giving the player to guide their character, because it works great when it's done right, and it's really bad when it's done not right.
Thing the 2nd:
Remember to WORLD-BUILD
Games are about exploring, they are about going somewhere else and doing exactly what you would do normally in a new environment if you didn't have any demand on your time.
I mean, what would you do if you were dropped off in Rio De Janeiro, London, Madrid, Sydney, New York, San Fransisco, Seattle, Paris, Copenhagen, Oslo, Moscow, Tokyo, or any other place you've never been with absolutely no limits on what you could do? You'd explore every goddamn square foot of it, right? The same thing goes for in-game worlds. We humans are curious by nature and want to discover everything we can about where we are. Or, at least I do.
There's nothing that destroys the flow of a story more than having an arbitrary roadblock because someone thought setting a linear game or level in a giant city would be awesome. This goes back to my first point in how much control you give to the player; give them more control and they will want to spend more time exploring the world. If you are prepared to let the player know they are playing an interactive-fiction story and the character won't want to go down the 5th dark alley they come across for some reason, that's fine, you can write any goddamn reason you want because the player understands they are not in complete control of the character they are playing.
Again, don't limit the options a player has after you've given them free-reign with the character they are playing.
A corollary to my second point, when you world-build, make things interesting, and give them a sense of internal logic. I just finished re-reading Dune, and I feel it is a smart example of world-building because everything works together; the Sandworms, the desert, the Fremen, the Fremen tools to survive in and exploit the desert, the Spice and why it is a commodity in such demand throughout the galaxy, they feel like they evolved, rather than were just placed there out of convenience, or to serve as a deus ex machina.
Thing the 3rd:
Watch the expositional dialogue.
No one in real life talks like that, and you can't take people seriously if they do. Internal monologues are risky, too.
Thing the 4th:
The writing does not carry the story entirely like it does in a book, or a movie.
Again, this goes back to arranging an understanding with the player on whether or not they are role-playing the character, or they are participating in a work of interactive-fiction.
