Surprising there's no threads about this game, as long as the beta has been going on, so I'll make one!
Mom got her beta invite a few days ago and I was watching her (and she let me start a character and play it myself, ssshhh, not sure if that's 100% legal lol).
So, I'm going to write a bit to get us started...
Diablo, for those of you who have never played the first two, is a 3-quarter overhead action medieval RPG that is basically about a hero (your character) fighting undead, demons, and other stuff and the main goal of the game is usually to kill the main demons (Diablo, Baal, Mephisto, etc).
Even though it is made by Blizzard, there appears to be no connection between Diablo's and Warcraft's universes.
You click your way through everything; you click the ground to move, you click mobs to attack them, you click items to pick them up. You gain XP and levelups and new abilities, and battle tends to be fairly fast-paced and you end up fighting many monsters at once and sometimes much more powerful "boss" monsters.
Now, for those of you who *have* played Diablo/2 before, here are some things I noticed immediately:
1). No Offline Mode. This is my only disappointment or con with the game that I've seen yet. You must be connected to the internet to log in and play. Having characters stored on BNET servers is a plus, but yet, it would have been nice to be able to log in and play locally without an internet connection required or a very small amount of net connection, OR, local-only characters. Yet another game I can't play if I have an internet outage or if I need to download stuff, as downloading creates horrendous lag that makes the game unplayable even if you're in single-player mode.
2). Town Portal, now a spell everyone has! That's right, the ole spell of Town Portal is back from Diablo 1, and everyone gets it during a certain quest. No more lame books of town portal cluttering up your inventory, no more scrolls, and no more "I wish a book of town portal would drop somewhere so I can learn the spell". It costs no mana (not every class has mana now), but it DOES have a cast timer (something new to Diablo) which I assume can be interrupted by nearby monsters.
3). Items never need identified unless they are Yellow-quality (or better I assume)! To identify an item, you simply right-click it, and there's a cast time (so you can't do it in battle). No more blowing your money on a scroll of identify, only to identify an item that vendors for less than what you bought the scroll for!
4). We have Right Click and Left Click abilities that carried over from Diablo 2, but unlike Diablo 2, some abilities can only go on Left, some can only go on Right, and new to Diablo 3 are buttons 1 through 4! Now you have 6 abilities and they can be swapped out (doing so has a cast timer and a short cooldown) to your pleasure once you learn more new abilities. Abilities also get runes that modify the abilities in certain ways, you can switch those in the same manner.
5). Potions now stack and have their own unique key (Q). They fill your health meter instantly, but they have a cooldown (30-45 seconds, something like that). Potions back in Diablo 1-2 did not stack, and in Diablo 2, they slowly refilled your life/mana unless they were rejuvenation potions which did so instantly.
6). There's a minimap now! awesome! No more leaving the map screen open fulltime.
7). Quests give experience now, and there are more quests. Furthermore, quest objectives are displayed WoW-style under the minimap feature.
8). There's a new, better WoW-style experience bar.
9). NO TALENT POINTS! I hated D2's Skill (Talent) Point System. Now, each character gets abilities that unlock at certain levels and you can choose what abilities/runes you use at any given time.
10). Crafting. There's a blacksmith/crafter you recruit early-game and you can spend gold to train him. You disenchant magical items for materials used in crafting new items. That way, when you want a specific item type, you can make a specific item type without praying that a shopkeeper might have it.
11). Terrain! You can use certain terrain features to kill enemies (you get extra experience for doing this!). Examples include cutting the chain on a chandelier to make it fall, or shooting a wooden support that's holding up a loose bookshelf to make it fall on stuff.
There's a lot more than what I listed here, so far I love the game, even though the Beta is quite short (You'll likely clear the beta content within 5 hours of playtime). It is addictive enough that you can replay it (especially with 5 characters to choose from), though.