Instance Difficulty Rating:
Level 10: Barrow Caves
A light run, drops some decent gear for lowbies. No drops if high levels join the run. Only one boss.
Level 20: Logar Windmill
Light and simple, boss can onehit tank if you do not silence. Boss is in 2 forms, runs away after first fight. No drops, only materials to make level 15-25 gear.
Level 25: Forsaken Abbey
The first challenging run, requires an actual tank to take damage off the bosses. Five Bosses.
Level 35: Necropolis of Mirrors
VERY hard without backup. Each of the three Androliers have a special thing they do when reaching a set amount of HP. Shadow splits into copies, Strength casts a spell that onehits anyone around the tank, and the final one has some other nasty feature (Havent killed him in a while). 6 Bosses, three skippable (Androlier bosses are in their own "rooms")
Level 35: Ice Dwarf Kingdom
Easy with backup, hard without. Hundreds of enemies attacking you at once, and they heal. and slow you. and rage. Bosses can onehit even a level 50 if they are not careful. Cook requires a strategy that is difficult to say the least, and if you try tank and spank he onehits tank. 4 Bosses. Last boss is easier than cook. Second boss is hardest (Cook).
Level 40: Mystic Altar
Easy to do with some lvl 50 backup. 4 bosses, first has a dangerous AOE, second is a spellcaster, third spawns guards, and fourth random-charges.
Level 40: Pasper's Shrine
Easy if you know what you are doing. Mobs cast silence circles that prevent spells of anyone standing on them. (I have never finished this instance, never needed to) Unknown bosses.
Level 50: Cyclops Lair
The "Main" endgame of the first Chapter. 6 Bosses, second is hardest, third is 3 bosses at once that gives different loot depending on how you kill them and is easiest. Final boss has 2 stages, make sure to keep OUT of the red orbs.
Level 50: Kaylin Shrine
The first endgame that cannot be done with "Tank and Spank" tactics. Each boss as a different strat. Second boss (A giant turtle) is a reccomended skip; can onehit anyone. (Does 360k damage)
Level 50: Treasure Trove
Pain the the
Hundreds of enemies all attacking you at once. Pathetic drops. Only time you should be in here is for Talomo's Memories for 50 elite skills.
Level 50: Ice Dwarf Kingdom REVAMP
Pain the the
as well. Only come in here for the 50 elites as well. Horrible drops. If you MUST have the skins, just do the level 30 version. Cook is almost impossible. One extra boss is added in; a Fire God. 5 Bosses.
Level 55: Hall of Survivors
Main endgame of Chapter 2. 7 bosses, each very hard. Recommended 35k HP and 50k Def on main tank for a full run. VERY good drops.
Level 55: Lair of the Water Dragon
1 (?) boss. Farming instance similar to Windmill. Drops materials to make very rare items
Level 55: Naga Acropolis (Zuhuridon Stronghold)
Unknown Bosses. Very hard, must kill Naga king Shaarleedah to get in. Drops good gear for stats.
Level 57: Dungeons of Dalanis
Farming instance. Kill first boss fast. 5(?) bosses. Drops very good level 57 purples.
Level 57: Lair of the Demon Dragon
1 (?) boss. Farming instance like LotWD and Windmill. Boss drops materials to make rare accessories.
Level 57: Hall of the Demon Lord
4 (?) Bosses. Very hard difficulty. Demon Lord is final boss, must kill Demon Dragon to get to him. Demon Lord drops the Sword of Fear, best one handed sword in the game.
In the future, who knows? There will be more and more, with increasing difficulty. As always, only people who pay the money will be able to do the later instances.