little tip: he's got a weak spot. it's a spot that glows red when u hit it and it's in that acid-sack-thing on his back. it's best to run behind him when he's stunned and then hit the spot. 1 or 2 hits with a normal hg will stun him again and from that point on you shoud be able to keep him in his place till he's dead. saves a lot of ammo (which you really only need on vet or pro, but anyway) so you can get those 11 kills. also (sidenote): you get more points if you kill multiple guardians in the waterdungeon with 1 trap (green is the largest trap)
Most DLC are not worth the money. I got this as well as Dragon Age. For 5 buck I wished they gave us more stuff. There is very little action in this DLC and one guardian consume like 1/4 of your ammo. Half of this level is trying to draw the Guardians into a trap and it was way too short and not that interesting. Sheva's mercenaries dlc for an extra 2.99 is a ripoff too, but it is the best character there.
for a show of possibilities,its not bad..however, if resources are as hard to come by like in previous resident evil titles,it was very wastefull..