In this expansion, Onslaught was introduced, and with that, an enemy scaling per floor, and many lanes having different types of buffs. Among those buffs, there's one called "Vampiric". This buff allows any enemy spawning in that lane, to leech health from any damage dealt. This buff, in theory, isn't that bad. But, as it is randomly placed on lanes, both short(close to cores), and far(far from cores) lanes, it has the possibility to give enemies the upper hand in attacking it, and regaining health. And, yet again, it theory, this isn't bad, but, in practice, when enemies leech 60% of their health back in a single hit, it's absurd, and nearly unbeatable unless you have gear from a floor nearly 20 floors higher. I, myself have witnessed(On floor 24) trash mobs sneaking by barricades and tossing bombs at a core, while being barraged by several Flamethrower towers, and auras, while seemingly taking absolutely no damage. And even boss mobs leeching back and astounding 4 million health for every hit they land on either a player, or a barricade. This mechanic makes this game mode nearly unplayable, per floor, for someone using the gear gained on said floor. This "vampiric" buff needs to be taken down quite a bit, and frankly, I don't see how this isn't being complained about by anyone else. It's unacceptable.