3-level solo scenario, designed to be played cooperatively. The level design could be a little more interesting, but it'll keep you busy.
A three-level solo map. Hmm... it's big, but it often felt like I was running through the same areas again and again (even when I wasn't). There's a lot to kill, but finding the ammo/weapons you need can be frustrating. Beware of the second level on slower machines... you get an absurd number of baddies in an open area.