"Left 4 Dead with ratmen" is how I'll crudely summarise what little I know about the newly announced Warhammer: The End Times - Vermintide [official site]. It's a co-op FPS pitting heroes against hordes of Skaven in shoot-o-melee action, coming in the second half of this year from War of the Vikings makers Fatshark.
Warhammer 40K is more my bag than Warhammer Fantasy, so all I really know about the Skaven comes from Kieron in pubs. They're hordes of ravenous little ratmen, I get, but also giant rat ogres and sometimes ride in rodent wheels bristling with knives and lightning guns. Cool-o!
Vermintide will have five different playable heroes, each with their own weapons and equipment, and see them voyaging "from the top of the Magnus Tower to the bowels of the Under Empire" according to the announcement. They're pretty vague beyond that, though.
As for how it all works, a NeoGAF thread has a few more details supposedly translated from a Finnish magazine preview. They say one hero's a witch hunter with daggers and pistols who rages on Skaven because a rat took his eye. A fire mage, meanwhile, is called "a pyromaniac insane old woman", in the poster's own words, and "She is powerful, but if she keeps on doing spells all the time, she will heat up and could burst into flames and kill herself." That'll be the character for me. They also have talk of an AI director and collecting items. The info seems legit, given that it surfaced before the official announcement, but details might get smooshed in the process of being summed up for a preview, translated, then recapped for a forum post.
Here's the not-very-useful announcement trailer:
John called this 'Vermintude' by mistake earlier, and now proposes we make that its Official RPS Name. He's a pretty rude dude, that one. To the max.