I'm up for some MP later on as well.
But yeah, I've had a few close calls from the game not registering M1 being held down, or interpreting move-clicks as attacks. Nothing major though; all of my deaths have been from screwups.
I managed to kill the final boss in the main desert dungeon without ever dropping below 1/3 health despite him being a grappler, it being a CQC-style arena with a lot of minions, and me being a squishy caster. The only point where I was ever really desperate I just kept popping mana pots and teleporting around in a circle until my HP was a bit higher. That was on veteran, so I imagine Elite would probably be tricky enough that I could die if I wasn't careful. Which isn't really too bad, considering that a lot of new games these days have their normal difficulty mislabeled as "ULTRA SUPER HARDCORE DEATH MODE".
I've done a bit of MP with random people, and from what I can tell the main difficulty is when you're playing with 2-3 other casters because you might not see something dangerous through the haze of fire columns, ice spikes, and dozens of multicolored bolts. That might be misinformation, though, because I think I accidentally joined a "normal" game at some point.
On another note, I've got a spell scroll setup that I like quite a bit: a passive armor buff, healing (duh), and summoned skeletons of melee and ranged varieties. The melee skeleton has a long enough life that I can get 3-4 into play at the same time, and with the archers and thunder locus (thingy) I can drag bosses back and forth through a net of secondary damage.
Oh yeah, and I transmuted a blood gem chip that gives +15 hp regen per second. For a cowardly kiter like me, heh. :3
I actually sort of like how you can't combine ember any more; the transmutation makes it quite a bit more interesting.