Bought it when it was released few weeks back. Played about 90hours since then. I've been having way too much fun playing with a friend. So far I got a level 75 Pyromancer and a level 56 Conjurer + bunch of other low levels.
Only problem Ive had with Grim Dawn is that it keeps crashing way too often. Feels like its still in beta tbh.
Ive done grift 38 solo and I don't have unity or countess julia. Jailers are only mobs that can kill me if I just pay attention to whats happening. Its tricky but with vault+tumble I can "dodge" jailers about 95% of the times. Smokescreen is good too. Keep at max range so your sentries keep firing. Only time I die is if theres a blue jailer mob at the entrance of new level (No room for kiting and I run out of discipline to use vault). Its tricky to deal with one yellow with jail, its a nightmare to deal with 3-6 blues with it :(.
From my experience all the other sources of damage can easily avoided by just paying attention.. dont stand in the fire or poison puddles, vault away from thunderstorm, LoS lightning/electricity, kite frozen orbs, vault from frozen patches etcetc..
Unity makes this game easier obviously, but its not really needed in sc.