Warhammer 40k Orks are known for their tendency to go on murderous rampages just for the sake of it, but in Space Marine, they'll have a purpose. Machinima have a new Space Marine dev diary which reveals that the planet that Space Marine is set on is a factory world devoted to making Titans. These are colossal walkers capable of levelling entire cities with their giant, stompy feet. If the Orks get their hands on one, they'll paint it red and point it at the nearest human settlement.
As well as some story tidbits, we get lots in-game footage, and a look at some of the different types of Ork we'll be fighting when the game comes out this summer. In the video, the devs are coy about a hidden threat lurking in the shadows. We know it's Chaos . They look like this .