As a single player game, it offers a rich storyline. The game is oozing with lore. There are ancillary NPCs fully voice acted with their own dialogues about their friends and family which can be interacted with throughout the progression of events. That will go overlooked by many players, because there isn't any need to talk to Villager A who will tell you about life before the fall of Tristram, but for those that wish to delve deeper, there's a lot of substance there. On top of that are the books and monster lore hidden in dungeons and towns. One of the most interesting aspects of this were the diaries left by characters, such as Leah and Cain in Act 1. They will periodically update their entries as the Act goes on. :: MINOR SPOILER When Leah is following you in Act 1, enter her room for some unique audio clips ::
Gameplay-wise, I have some bones to pick with it. The old click control scheme requires heavy usage of the shift keys to get the most out of it. I had just finished Diablo 2, again, before Diablo 3 came out so that I could get familiar with the controls and storyline, so I'm not sure how clear the shift key usage is to new players, but I didn't notice a useful tooltip for explaining it. I also witnessed my friends playing without the shift key, and dieing a lot. They're making a slow progression through Act 1 Inferno, hampered by this and a few other things. A new idea for the game is making boss monsters actually large. In comparison to D2, the boss monsters take up over 1000% more screen real estate. It looks awesome, but in practice it can cause movement issues with the character, since clicking is both moving and attacking. My friend died to the Butcher in Inferno more than once by getting stuck in a corner and being unable to click past him before dieing.
As for the skills and abilities, they have a lot of multiplayer potential. The majority are single person buffs or DPS focused, but there are a few, such as the Monk mantras, that are team focused. I'm very interested in the PVP builds that will start coming out in a few months. Already, some broken single player builds have been discovered. Quite cleverly, a Wizard used one ability that reduced all incoming damage to a maximum of 35% of his HP, and another passive that caused him to heal over time. Sacrificing all of his vitality, enemies were hitting him for less than he was healing. Allegedly he managed to solo Diablo on Inferno. What I found the most interesting about this were the statistics for his build. Less than 0.5% of players were using that ridiculously good build. That either means that not a lot of people thought about it, or that there are other builds people are coming out with that are even stronger. The diversity promises to make playing with any new players a learning experience. "Oh, I've never seen that move before. What's it do?"
Fortunately, the community is large and open. After spending a lot of time lurking r/diablo3 (I avoid GD forums at all costs), I found that most posts are funny light hearted memes, or build discussions and gameplay tips. There are a lot of videos of people showcasing their talents in game, as well as plenty of Error 37 criticism. Playing online, you can expect to find a diverse assortment of people, but don't expect too much discussion during gameplay, because it's pretty hard to type and use the mouse at the same time. Look for places like r/diablo3 and diablofans.com for real discussions.
It's a tough call, but I'd have to say that Diablo 3 is a pretty good game. The gameplay is familiar to veterans, though not perfect, and the skills and abilities have a lot of potential for discovery and unique builds. The community is awesome, but you're not going to be talking much while playing, and the lore is astoundingly vast. The biggest bone I have to pick with Diablo 3, I can't really talk about. I don't want to spoil the main plot for anyone, but the characterization and ending leave much to be desired.
Overall :: 4/5