X-com style game set in any universe would be absolutely fantastic.
My own personal pet project over the past couple of months has actually been a pen and paper tabletop game that is a loving homage to X-Com and Syndicate; it kind of plays like Delta Green.
Basically a similar premise to X-Com in that aliens have attacked and they need to be neutralized, but in this setting, the aliens have attacked after Megacorporations have already taken the place of most forms of government, and instead of X-Com being created, each corporation has financed and outfitted their own PMC. Players are new recruits for a PMC of one of the various corporations, and can augment their body ala Syndicate. Enemies other than aliens include rival PMC Operators, and weirdo androids.
It's basically crammed full of things I like. I'm not a programmer or an artist, so I went the route of a pen and paper RPG. Most resultion is based not on 1d20 (or even 2d10), but 1d8+1d12 (it gives a more even distribution).
tl;dr, X-Com/Syndicate meets Delta Green/Dark Heresy/Shadowrun.
Nothing in it is *directly* from the settings, just inspired, kind of like Forever War being Joe Halderman's answer to Starship Troopers.
There is also a moon colony, but it's not really Doom-inspired; more along the lines of 2001 Space Odyssey. No fancy video game unfortunately though! It'll just be a PDF file, and I am eventually going to shell out some money to commision a cover and a few page spreads of artwork for the inside.
Didn't mean to go off on a tangent, but everyone talking about X-Com made me spill.
