Just ran this. I think I was a bit over the level range for the instance (75 DK, 4x 76 shaman). I found everything except the last boss quite easy. Only one wipe (on the last boss because I didn't realize a wall went up and all 4 of my shamans were trapped on the wrong side - couldn't attack or heal my DK LOL).

The nice thing about this instance is its SUPER fast. I think theres like 12 pulls in the entire instance. The first boss is in the first room. Ok, a couple of tricks.

1) Skirmishers should ALWAYS be killed first. I basically pulled the skirmisher, dropped a death and decay, then went all out on the skirmisher as fast as possible. Usually when they were about 1 volley from dying they'd charge my shamans but the next volley took them out so my shamans hardly got hurt.
2) Shadowcasters - they do some sort of confusion attack - not sure if tremor totem stops this because I didn't have it out when I was fighting them but it made me waste a ton of mana healing after my guys lost the debuff. Take these guys out second.

The first boss is really easy, the issue is he has 3 pulls before him and once you make the first pull, each pull happens automatically after that. After the 3rd pull my shamans were at ~5% mana. I had about 7 seconds to drink and then start the boss fight at 40% mana or so. Fortunately, the boss was easy. I don't remember him doing anything special, just a tank and spank.

Not much to say about the pulls before the second boss...It took me a little while to figure out where to go after the first boss' room (hint: you can walk on the spiderwebs). Anyway, when I got down to the second bosses room, I was getting random elites coming at me periodically, and there was a couple pulls. I finished off the single elites and took care of the pulls (the giant guys are actually quite easy). After that, I saw the boss come in (giant spider). He had a swarm of non elites attacking him. I waited until he had killed all of them before pulling him. Nothing special here either, just a tank and spank. Honestly it was so easy I wasn't even sure it was an actual boss until I looted it and got the blue item. Now you drop down the hole and move towards the last boss.

I don't even remember there being any pulls before the last boss other than his 2 guards...

Last boss, first thing to remember is once the battle starts he puts a web wall up around the ring hes in. Any of your guys outside that ring are effectively locked out of the fight. I was really hesitant to move my shamans inside the ring because it looks like you'll be so close you'll aggro him. I put them on the lip around the ring. Be careful with that too though as one of my shamans was "inside" the wall but still couldn't attack until I manually moved him forward slightly.

The actual fight is really hectic. I downed him the first try (once I had my guys in the ring anyway) but I was at ~5% mana at the end of the fight due to massive healing mana spent. I also lost 1 shaman near the end. I think this fight would have been a lot tougher if I was a couple levels lower (I had just gotten the next rank of water shield which is 100mp5 instead of 50mp5).

I didn't have a plan really other than I knew the boss would spike my DPS and I had to choose what to do about it. I thought about it and decided to just heal through it. In hindsight it was the correct choice because my guys weren't spread out enough to strafe-dodge the spikes. If I did this on heroic I'd probably leave my DPS in 1 stack so I could more-easily strafe dodge (while tanking the boss facing my DPS). Once the boss goes underground (I DPSed too slow and he did this a few times), I just kept pulling in the adds. It seemed like each time the boss went underground there was always one elite with 33k hp or so that had to be killed before he'd come back. THeres also some non elites that don't do much damage. I had used my fire elementals on boss #2 so I couldn't use them here, but if I was doing this fight again I would open up with 4 fire eles, bloodlust, trinket etc and just get a couple seconds of aggro before letting a massive volley loose. Doing a lot more frontload damage probably would have saved my mana in the end.

So all in all, not a bad instance. The last boss was too much micromanagement to enjoy so I'm not sure I'll ever even try this one on Heroic, we'll see. When I was looking for tips I couldn't find anything about this instance except the skirmishers and the last boss so I figured I would do a quick writeup in case someone else needs some info.