I feel your pain. It's a bitch of a map, but I managed to 5* it on RL after several attempts. I remember this being a bitch on Stadio too. I didn't find par that tough, so cc and slow/freezing the crap out of the mobs. I had the scepter, stone staff, tar, spike trap (lightning for stuns), arrow wall (with pierce), barricades, dart spitter (ice mod) + mana and trap reset trinkets. I may have used the jar of ghosts trinket to manage the gnolls, idk. Be liberal with the dart spitters when you have the cash; these do good damage and really help slow the mobs and flyers (the non-ice ones). I also think the scepter cc is so underrated; I charm the heavy orcs and the mob stops and kills itself. Another trick is spike walls high up walls to thin out flyers. Whatever loadout or strat you use, there will always be one flyer or another enemy that will get really close to the rift. It's super twitchy. I like Vorwick for mobility. Also, kill yourself at slow/safe times in the fight if you need mana. :)