Take an Elite-style game like Flatspace II. Set it in a cartoony universe where Zombies and Ninjas are waging an interstellar war. Tool around in a "starship" that's more like a Buick with a stardrive and lasers. Wage space battles against, among other things, space-going galleons and pterodactyls, and trade goods like cheese, paper, and kittens--no "industrial goods" or other boring stuff here. All to a loud, frenetic neopunk score--that's Ninjastarmageddon!.
As far as the gameplay goes, Ninjastarmageddon is familiar: You control a single ship, and tool around the galaxy, trading goods, fighting battles, going after pirates as a bounty-hunter, going pirate yourself, and finding and looting derelict ships.
Over time, you upgrade your ship with better weapons, more cargo capacity, and the like. In other words, lots of different options, in a semi-randomly generated galaxy, providing a high level of repeat playability. One difference from other titles, though, is that the game can be played either in 3D or 2D top-down mode; 2D makes combat a tad easier (harder to aim when you have to deal with the third dimension), but 3D is awfully pretty, in a cartoony way.
What makes Ninjastarmageddon fresh, though, is its cheeky, gonzo attitude--pirates and ninjas and zombies, oh my. Sometimes it seems like the game industry is utterly devoid of humor--but this game is cheerfully out there, and while you shouldn't expect guffaws of laughter, you will find yourself chortling at times, as you desperately try to find a market to offload the damn kittens.
Excellent fun.