I'd make a joke about Chris Carter writing it, except this story was actually resolved.

So it's like Deus Ex. Is the gameplay half as crappy as that circus of terror?

Well let me give you a little perspective. I loved Deus Ex. I couldn't stand this. Chances are you'd burst into flames on contact with the controller.

Seconded. One wonders if the original 2nd half of the script got destroyed and they just made shit up from that point on.

I also enjoyed a protagonist getting the female lead pregnant, despite being a reanimated corpse.

I will share with you what I know. The asian guy was being compelled to murder people for what seemed at first to be a voodoo-ish ritual but was really something designed to help one of the 'clans'. More on them later. The female lead was originally the cop that was assigned to catch the asian dude. Eventually it's discovered that this ritual, is, as aforementioned, being performed at the behest of a 'clan'. There are I don't know how many clans ruling the world in a sort of illuminati-ish arrangement, each clan has a color and they're always feuding. As what I suppose is a result of the ritual, eventually it snows so much that the world is more or less drowned in snow. So asian guy and sassy latino cop chick go off to save the world from the clans. In their snow plow.

Oh, and the asian guy has magic powers.

Oh, and the purple clan is the internet.

Is the entire game ddr and button mashing or is there actual game play?

Yes, it is. No, not really.