Beat normal today; the last couple days have been great in terms of progress, I also found two legendary items. The last parts of Act III are pretty impressive, especially that last temple; very creepy, and surprisingly challenging. The last boss (I'm sure you can guess who it is)...hmm. I had to use a lot of potions and almost died multiple times (still got a one shot tho, woot). Honestly the truly hardest thing was the frame rate, which exploded once I entered the room; lots of effects, shadows, etc...they'll need to address that.
It's quite clear this is going to be a truly great game once it's finished (I can't wait for Act IV). The level of customization is engrossing, I constantly find myself staring at the passive tree gaming out what I'll get when. And even the introductory difficulty level is challenging. I rarely died in the early stages of the game but had multiple close calls, and all the major bosses keep you on your toes. And despite being such a long ass game, I can't really say I got bored with the visuals or gameplay; Act II's pyramid is the only part I got a bit tired of, mainly due to farming it (and the grueling elemental mobs).
I'm gonna be spending a lot of time with this game