I make them for my own entertainment, and hopefully yours. Most of the time, the intended message of these games is something to the tune of "Zombies are cool. Horrible things From Beyond are cool. Apocalypses are cool. Come play with those cool things, with me!"
Which doesn't sound like much of a message, in terms of social whatsits, you know? I'm not trying to create or forward a more just world through the medium of game design, I'm just trying to invite everyone to come play with all this cool freakin' stuff.
As it turns out, though, inviting everyone isn't as small a goal as I used to think.
When I do game art, in big batches, my tendency follows right along with most media - there are more men than women. The men tend to be in more active poses. When there are colours (I work in silhouette and abstract a bunch; there aren't always), it's easy to make everyone white.
When I write examples and touch on matters of sex or gender in a game (neither of which happens much; I'm much more interested in telling you about how to roll dice - but there's some), it's easy to just say "Bob and Joe do ABC", and just carry on. Saying "Sandra and Jane do ABC" isn't what comes out if I'm just rattling away at the keyboard.
These are instances of bias on my part. I came by them entirely honestly; I'm a white guy (also straight, able, cis, and so on), and it's easy to write to people like me, and to write and make art in the tone of much of the media I've consumed over the years. I'm not doing a wrong or terrible thing when I do that, and I don't think others are either - but I'm also not achieving my goal of inviting everyone.
To make it that goal, I've come to find, I need to attend to two things. I'm not that good at this, yet; it's a skill in the making I'm talking about here, not a position of enlightenment I'm talking from.
The first thing is to seek neutrality instead of normativity. Which is a mouthful, but. If it's normal for media to do all those things (heavy on active men with fewer and more passive women, all relationships shown being straight ones, all gendering obvious and binary, everyone fully able...), but the audience of everyone isn't like that, then what's normative isn't what's neutral. And people notice that. There's a chunk of everyone that doesn't feel like this invitation is directed toward them, when it's given that way. So if I want it those people to feel like it is (and I do), then getting rid of the "normal bias" is important.
That doesn't mean everything I do should show a complete range of all those things. If I want to do a project about a group of five people from the same small town running through a forest, I might never touch on romance in any way. I might never show ethnicity. But the moment I start doing so, I've gotta ask myself if I've defaulted to that normativity, and just how I should elbow it out of the way - show a good and roughly representative range? Invent a different standard that suits the project?
The second thing is to aim for active inclusion. Which is all about a deeply shitty thing in the world that deserves paying attention to, and it's this:
There is a fairly significant chunk of "everyone" that is used to being UNinvited.
If the "normal" in the medium of games and the community surrounding gaming is to make (petty and mean) jokes about a given group of people, then that chunk of "everyone" has every reason to walk right past anything I make with the assumption that they aren't invited. Being quietly neutral may mean that those folks will be more comfortable than usual if they do stick their heads in and have a look. And that's good, but it's not the same.
If I want to invite everyone on the playground to play soccer with me, I need to be talking to everyone. Not just the people like me.
And I need to recognize that the kid that has been excluded from most of the playground games does not believe I'm inviting them when I shout. If I want to invite everyone, I've got to walk over to that kid and say, hey. You too.
I'm working on it.