The first thought that springs to mind is "this place is big". Crowded alongside 39 other raiders, the scale of the instance seemed fitting; accompanied by only nine comrades, we're dwarfed by it. Nowhere is this more apparent than during boss fights, which feel like some strange amalgam of the level 60 and level 70 experiences.
Trash inside Naxx is eerily familiar. Whirlwinding deathknights, gargoyles with stoneskin, even Frogger are all ready to welcome you back into raiding with open arms. And no mention of the residents of Naxxramas would be complete without Mr. Bigglesworth
-- yes, for those cat-haters among you, he's still there.
The winged nature of the instance means that you can pick and choose which bosses to do first, although you need to clear all four quarters in order to face Sapphiron and Kel'Thuzad. Renamed from their level 60 counterparts, the instance comprises the Construct Quarter (Abomination Wing), Plague Quarter (Plague Wing), Arachnid Quarter (Spider Wing) and Military Quarter (Deathknight Wing).
Construct Quarter Bosses: Patchwerk, Grobbulus, Gluth, Thaddius
There are no real surprises in this quarter. The 10-man version of Patchwerk is a hard-hitting, hateful-striking sack of flesh and bones that still requires fairly intensive DPS and healing, but should not prove too difficult for a reasonably geared raid. Grobbulus became a zerg at 70, but at 80 it's back to kiting, positioning and dealing with slimes.
Gluth has moved away from fearing and is now tauntable, making the tanking side more controlled; however, you still need to deal with his health-stripping Decimate and, of course, the inevitable flood of zombies. If you don't have a paladin or mage this might be tricky.
Thaddius is as enjoyable a fight as ever; add tanks get teleported to the other side, rather than knocked back, removing some margin for error. The polarity switch mechanic remains intact, so you'll need some strategy for dealing with it. Practice on the level 60 version certainly helps here, and we have visions of struggling PuGs failing to determine left from right... it happens in Mechanar heroic, so it'll happen here!
Plague Quarter Bosses: Noth the Plaguebringer, Heigan the Unclean, Loatheb
The Noth encounter hasn't changed a great deal; again, you need some way to deal with the adds, but you probably have an offtank who can take care of them. Heigan is a lot of fun; if you haven't done the encounter at 60 or 70, it would probably be a good idea to try it now, as the 'dance
' is the same. Fortunately for when you wipe, the gauntlet before his room doesn't respawn any more; also, the teleport mechanic's been removed, so the fight really is just about learning where to stand and when.
The healing mechanic behind Loatheb's been changed to better suit the smaller raid. Instead of a one-minute cooldown on spells, he casts an aura that reduces healing done by 100% (similar to RoS phase 1). Healers must time their casts to land when the debuff fades, while everyone but the tank races to grab spores to provide maximum DPS. Depending on the healing classes you have, this can be tough or easy -- for example, Power Word: Shield helps a great deal. Arachnid Quarter Bosses: Anub'Rekhan, Grand Widow Faerlina, Maexxna
Anub'Rekhan is a simplified version of his former self, with no adds initially, though they spawn one at a time during the fight. The locust swarm ability and thus the need for tank kiting is still central to the fight, though you probably won't need to do this more than once. Faerlina is similar, although there's no need to mind control adds any more -- offtanking them is sufficient.
Maexxna is fundamentally unchanged as well, but due to the nature of the fight, is likely to be one of the trickiest encounters in here. You'll need to be able to deal with raid members who get Web Wrap and provide enough healing that the main tank doesn't die during Web Spray. Removing poison and controlling her enrage are also important. Another one that is trivial at 70 but will require effort at 80.
Military Quarter Bosses: Instructor Razuvious, Gothik the Harvester, The Four Horsemen
At level 60, fighting Razuvious meant giving your priests a starring role and turning them into tanks. Well, sorry priests, but your number's up; at 80, the 10-man Razuvious has two adds, each of which can be controlled via a crystal. The basic idea's the same; offtank an add while the other tanks the boss, switching as required. For those who remember dodging Razuvious's deadly Shout via line-of-sight, you'll perhaps be glad to know it currently has zero effect, though this might change.
The Gothik encounter feels very similar to the level 70 experience; the adds are pretty trivial and most of the fight is spent waiting around, but given reports from the 25-man, it's likely this will be tuned to be a little more challenging.
Many people were interested to find out what would happen with the 10-man version of the Four Horsemen, since fielding four tanks is overkill. Firstly, Highlord Mograine's gone missing and our good friend Baron Rivendare has stepped in to take his place; secondly, the horsemen move to their corners of the room when engaged, removing the need for complicated positioning at the start of the fight.
Rivendare and Thane Kor'thazz are both traditionally tanked, dealing melee damage and using a normal aggro table. However, the two other Horsemen -- Lady Blaumeaux and Sir Zeliek -- deal spell damage to the raid member closest to them. This means you can use any class to tank them, swapping in your actual tanks once their horsemen die. The mark mechanic is the same, so you do need to be wary of debuffs and swap positions -- ie tanks need to relieve each other, DPS and healers should move if their marks get too high, etc.
Sapphiron and Kel'Thuzad
After defeating all four quarters' end bosses, you'll be able to access the Frostwyrm Lair and face Sapphiron. This frost dragon is unchanged from the level 60 version; like his previous incarnation, he has a frost aura that ticks constantly, but this time it's healable (so you don't need to be kitted out in frost resistance gear). After avoiding cleaves, tail swipes and blizzards, it's a matter of staying behind ice blocks to avoid his deadly frost breath when airborne, and simply burning him down -- practice on the level 60 version will undoubtedly help, again, as deaths can quickly cascade.
Kel'thuzad, the fight which represented the pinnacle of vanilla raiding, is still an interesting encounter but you'll find it a lot easier than before. Phase 1 is all about dealing with adds, phase 2 requires some awareness and positioning (don't stand in the big red circles of death), phase 3 introduces two adds (finally giving your offtank something to do while you burn him down). Not really the hardest fight in the world.
Having seen Naxx cleared multiple times on beta with groups of mostly-Sunwell geared players, it's clear that the 10-man version as it currently stands occupies an interesting space in raiding. It'll keep the guilds who are ahead of the curve occupied until they can start into the 25-man version, but will provide a decent challenge for raiders who don't have cutting-edge gear now.
It is something of a loot pinata and, for people who were expecting the epic encounters of level 60, perhaps an anticlimax of sorts. The mechanics that were so novel at level 60 have been reused since, and so multiple-mob fights, waves of adds, even poison clouds on the floor are all things we're used to dealing with now.
Fortunately this just means the instance is going to be fairly accessible even to those who haven't seen it before level 80, though it's really recommended that you try to see it now if you can, or you'll just get overwhelmed. There's also the disclaimer that more tuning needs to take place, both in terms of individual class balance and the bosses themselves, so things that seem a little too easy now will most likely become a reasonable challenge later on. Still, we're looking forward to it, and can't wait to try out Naxx 25 soon.