I watched the video and was amazed by the game, admittedly more amazed than I had ever been.  Despite it being a little too bright, and just a bit too fuzzy, it was perfect in every detail.  The video begins with a quick, little tour of the Blizzard offices, which all focuses in on Diablo II playing in what looks to be a some sort of conference room.  The video focuses in on this, and gameplay dominates its footage for the next eight minutes.  Some information I present here may be a little off as it was hard to read words due to the fuzziness of the video, and I did the best I could.

The Amazon

First we are treated to footage of the Amazon, the first shots showing her with the inventory screen up.  This screen bears little similarity to its Diablo predecessor in that it has 10 spots for all of Diablo II's items than can be equipped.  The first thing they try on is some armor, to show off Diablo II's component system which changes the character's look according to what you put on them (unlike Diablo, which really only changed when you equipped grades of armor, leather, chain, or plate).  Diablo II makes changes for everything you don whether it be helms, boots, or armor.

 We also see that Bows now require a complementary quiver, as now they all don't have unlimited shots and such.  It also shows the equipping of a belt, one of Diablo II's new equipment, but doesn't show what the belt does.  The potion bar now seems to be a sort of pop-up bar, which displays 16 slots in this particular moment, I think that might be subject to what level you are, or perhaps it is the function of belts.

Next comes the Amazon's skill bar popping up, showing that each function button for the mouse is programmable, you can set either button to a skill or basic function in Diablo II.  The Fire arrows are chosen and we watch as the Amazon begins to move around the level.  Diablo II has done away with Diablo's eight paths of movement for a true 360 degrees of freedom.  The Amazon's stride is very nonlinear, just as it should be, it looks like you could almost run in circles if you wanted to.  She also bursts into a run here and there, and I must say that she's pretty quick.

 She comes upon a "Quill Rat" (a porcupine-like enemy), which displays its name near the top-center of the screen when the cursor is positioned over it.  One Fire Arrow spells death for the critter, however, and it drops some gold.  Still standing, we watch as the daytime-nightime transition is shown, complete with phases in between that simulate dusk and dawn.  Its quite fantastic to watch shadows bend in the Amazon's light radius as she blurs past a grove of trees.

Next, a group of Fallen Ones attempt to attack the Amazon, traveling with the pack mentality they try to overwhelm her.  With her Fire Arrows she picks them off without any real damage.  In the dark, the colored lighting of these arrows really stand out, as do the explosion they make when they hit a creature.  There's a transition in the video and it shows the Amazon attacked by Quill Rats, and a zombie called a "Hungry Dead."  As she takes them out, I watched as her mana sphere seemed to slowly regenerate over time, a new feature.

A new arrow is selected, called the Cold Arrow, and it is used against another of the Hungry Dead.  This arrow causes a creature to become much slower and be suffused with a blue glow.  The arrow is changed again, this time to Multiple Shot, which fires three arrows at once.  Using this skill, the Amazon takes out two Fallen Ones at once.  Another skill is selected to finish off the slowed zombie, this one is the Exploding Arrow.

This arrow, upon impact, explodes in a beautiful corona of fire that makes an equally impressive splash of colored light.  This explosion kills the zombie with grim satisfaction.  Two Fallen Ones receive the brunt of her next shot, they both die in the explosion, it looks to have splash damage as well.