One idea I have for Cosmic Cutthroats is to release dimension books, that would work as standalone settings. I know of one dimension-travel game that does that, so it’s not new, but it would still be fun.
Invulnerable 3rd Edition could be a sourcebook for CC, the dimension of Earth-Omega. Invulnerable itself grew out of a urban fantasy/horror game called Dirge that saw limited release online before I pulled it. In my mind, that world always had the depressing, poetic name The Vale of the Downtrodden. The sketchy setting for Wormholes & Waystations, the Sentient Assembly, would cover your space opera and giant robot genres. And I’ve always been a fan of post-apocalypse, settings, though I’ve never done more than tinker with a post-apoc setting. I have a name though, Dross Prime.
But for the core book itself, what will it play out like? How do you run a dimension travel game? I think the archetypal plot for CC will be The Seven Samurai. You’re wandering mercenary scum, you’re sucked into a local fight that’s not your own while you wait for the next dimensional gate to open, you grow to care for the locals, then, the big showdown. Of course, in a dimension travel game, you should be able to run any kind of plot. I see adventurers as money-grubbing trouble on the hoof, so Time Bandits works really well as a model, too. A major goal of most adventurers will be filling up their Edge meters, because that fuels all kinds of crazy stunts they’re capable of, so there will be a certain amount of Fear and Loathing in Las Vegas, too (note: also another Terry Gilliam film). Ultimately, the adventurers’ Qualities tell you what will grab the characters themselves and make the action personal.