Shatterbone was the cause of death for my first barb. I was in a group and we were trouncing everything. I saw a bunch of those mace wielding goons and leapt into a pack. Shatterbone popped out of the ground, everything hit me with the windup attack, and I was dead in a fraction of a second. Good lesson to learn and fortunately, I was only lvl 19.
I always found waller champ packs to be one of the more dangerous things out there because the walls can prevent you from dishing out damage and can keep you corralled in ground effects.
On the molten front - be careful of invulnerable minions + molten, because when you kill the boss all of the minion bombs will go off together. You may be able to take 2 or 3 bombs, but getting hit by a whole pack won't end well.
On the cynical front - lag can "one shot" you pretty good too.
After losing a lvl 54 DH and seeing a few friends die off as well, I'd like to make a general observation about a common cause of death for levels 30-60.
Most pre-60 deaths I've seen result from attempting to farm areas based on your weapon / killing power rather than your level. It is all too easy to get a reduced level weapon and start farming an advanced area simply because you can wipe out most mobs and champs quickly. Actually, however, it can disguise the fact that you are quite underlevelled for an area and you could be killed quite quickly by certain types of champ packs.
It is a risk/reward trade off. Sure you level faster, but unless you are very selective about the areas you farm (and how you farm them), you are exposed to much greater risk.
Just a cautionary word that just because you do 3x more damage than a standard character of your level doesn't guarantee you can safely handle harder areas.
I'm curious about what will kill me - what should I be on the lookout for? What are the widowmakers in hardcore? I have two 60's in SC, but I simply feel that this has only taught me to be careless.
I'm in A2 NM, and I'm finding myself fearing fear itself. Will those frozen orbs kill me, or will they hardly scratch? Will this big hammerarm-swinging-beast-thing in A4 one shot me? Not being able to learn from experience (IE death + respawn) is...killing me!
I'd love a list of what to look out for, which to me basically mean what will one and two shot me, what combos kill the most HC, what Acts kill the most HC, etc. I searched for some guides on this to no avail. Thank you.
A lil about-me: long-time Diablo fan. Never ventured into HC, and I'm feeling the need for some extra excitement with this title. Furthermore, I'm a "social" gamer and find that the HC community may be a little more fitting for my style.
beware of standing just on top of arcane sentry. It is a small chance but still its there - that arcane sentry will be spawned just under your character. It is also hard to see , since your character is kind of covering it. So, general advice - if you are loosing health quickly, dont think what - but move! now! (soldier) :-)