Finally got to try some co-op with this game yesterday.
My buddy had never played a Dynasty Warriors game before, but once I talked him through the basics of the game we were having a blast. Coordinating our efforts, taking down bosses, and just having fun. We couldn't A Rank a whole lot, since he took quite a bit of damage on some stages, but I can just go back and clean that up later. We unlocked Ghirahim (he hasn't played SS, so he found his introduction a bit odd; got a laugh out of me). Oh and those "Quiz" type maps are hilariously easy with 2 people. We had no trouble A-ranking those.
I'm going back and cleaning up some of those maps we didn't do so well on, and in the map where you get Ghirahim's level 2 weapon, I can't find that 2nd Gold Skulltula. It appears on the map, I go to the general location and hear it's scratching, but can't actually spot it before it flees. Part of that probably has to do with the fact that by that point I'm being hounded by a hundred angry Cuccos and I don't want to sit still very long. I'll try again in a bit.