How to sucessfully rampage ultimate dungeon up floor 15+:
You have to be in balanced group. Good is: 1. mage with healing scrool (or could it be ranger, but mage is better thanks to fast mana regeneration), 2. ninja (or other fast-moving character with lots of HP) who will just attract enemies and do cyrcle around others, NOT attack them, 3. and 4. is good combination vampire hunter and pyro for theyre good damage. With this group you will make it far.
Everyone is complaining on prices of keys. Why? Nobody can just open everything what he just found, and it is perfect, and if you are runing ultimate dungeon, you can earn 10 - 15k on single run, so whats a problem...