Achievements

Storming the Citadel (25 player) - Defeat the first four bosses in Icecrown Citadel in 25-player mode.
The Plagueworks (25 player) - Defeat the bosses of The Plagueworks in Icecrown Citadel in 25-player mode.
The Crimson Hall (25 player) - Defeat the bosses of The Crimson Hall in Icecrown Citadel in 25-player mode.
The Frostwing Halls (25 player) - Defeat the bosses of The Frostwing Halls in Icecrown Citadel in 25-player mode.
Fall of the Lich King (25 player) - Defeat every boss in Icecrown Citadel in 25-player mode.
It's a Trap! (25 player) - Survive the Ice Jets in Icecrown Citadel 25-player mode.
Boned (25 player) - Defeat Lord Marrowgar without anyone taking damage from Bone Cyclone in 10-player mode.
Thirty One (25 player) - Defeat X of Lady Deathwhisper's adds with her bombs and then defeat Lady Deathwhisper in 25-player mode.
I'm on a Boat (25 player) - Claim victory in the Gunship Battle in which every raid member visits the enemy gunship only once in 25-player mode.
I've Gone and Made a Mess (25 player) - Defeat the Deathbringer with fewer than X raid members suffering from Garrote in 25-player mode.
Dances with Oozes (25 player) - Defeat Rotface without exploding any oozes in 25-player mode.
Festergut (25 player) - PH in 25-player mode.
Spin the Bottle (25 player) - Defeat Professor Putricide with no member of the raid having been hit by a bottle in 25-player mode.
Blood Council (25 player) - PH in 25-player mode.
Once Bitten, Twice Shy (25 player) - Defeat the Blood Queen while having been a vampire in 25-player mode.
Healbot (25 player) - Heal Valithria Dreamwalker in under 31 minutes in 25-player mode.
Sindragosa (25 player) - PH in 25-player mode.
Been Waiting a Long Time for This (25 player) - Allow Necrotic Plague to stack to 30 before defeating the Lich King in 25-player mode.
Neck-Deep in Vile (25 player) - Kill every Vile Spirit that spawns before it explodes and then defeat the Lich King in 25-player mode.