I almost took down the North Western one, but he got to turn into me twice with all those damn cannons and I ended up eating it. Give me a few more times and I'll take it down.
EDIT: Goddamned optional objectives! Not only was this memory long as hell, I missed the optional objective popup (surprise, surprise). You're supposed to use two guards as human shields. There's no real need to do that in this memory. It's deliberately there to give the player something to do. It doesn't even make sense.
I'll have to do that memory again damn it. Part of me, the very, very, very petty part of me that only comes out at extreme frustration, wants to go back and rate every memory at one just to screw with the metrics (if they're taking them as such).
EDIT, EDIT: So, I've got a bit of an issue. There's three buried treasures left in the world, and I'm all out of treasure maps. Are they some kind of online thing?