"We've always said we wanted to create a story about taking one human through [a huge story]," said Mass Effect 2 project director Casey Hudson during a lengthy demo of the game. "And that human is Commander Shepard." As planned, players can carry over their saved data from Mass Effect, with character choices and gameplay decisions impacting the events of the dark sequel.

The real surprise coming out of E3, however, is that it also isn't a spoiler to say that Commander Shepard dies in Mass Effect 2.

In fact, plenty of major characters in Mass Effect 2 can die before the end of the game. And if Shepard or any of his companions die, and you carry over that data to Mass Effect 3, those characters won't make appearances in the final game of the trilogy.

Before we got to a fatal scenario, BioWare showed us a section of the game where Shepard and company infiltrate a building to find a mysterious assassin. Hudson explained that Shepard is tracking down the mysterious disappearance of humans across the galaxy, a quest that will culminate in a significant final mission--a mission that will see your decisions impacting every stage of the climax.

The first gameplay segment shown amounted to a conversation between Shapard and blue-skinned alien Liara in a flying car, a scene first shown at GDC. BioWare has stepped up the cinematic camera angles in Mass Effect 2, and not to a gimmicky level--nearly every shot during the conversations was beautifully staged, including plenty of dynamic camera movement.

Liara eventually dropped Shepard off at the target building, at which point the party quickly captured a guard, leading Hudson to introduce the new "interrupt system"--a new way for players to physically and abruptly end a conversation.

During the guard's interrogation--"Tell me where the bomb assassin is!"--players will eventually see a flashing exclamation mark in the lower left corner marked with the left-trigger icon. Upon pressing it, Shepard simply pushed the guard out the window, leading one character to quip, "So when do we read him his rights?"

Shortly thereafter, Hudson detailed a few of the new combat systems. Mass Effect 2 will now allow players to fire off abilities without pausing the game, in addition to issuing move and attack orders for independent party members. All of this lends itself to a more dynamic combat scenario, with a great focus on scooting and shooting.

Of course, the abilities themselves have been bolstered by new additions. The Bionic Pull will allow players to yank enemies out from behind cover, while concussive rounds physically blast characters into the air. There are nine new weapons classes in all, including a new heavy weapons system.

Now we hit spoiler territory--or, at least, light spoiler territory. As the ending--and the middle--of Mass Effect 2 will change depending on your decisions, to call anything a true spoiler seems pointless. Even still:

DO NOT READ BELOW THIS POINT IF YOU WISH TO REMAIN ENTIRELY UNSPOILED.

Following the infiltration scene, BioWare had two more quick glimpses of the game. The first was of various other planets, which will now be more varied in design, or "like a science-fiction painting come to life," as Hudson put it.

But the really interesting stuff was in the concept of major character deaths. Depending on your choices, any main character can permanently die in Mass Effect 2, which will lead to some fairly stunning plot twists.

To illustrate this point, BioWare skipped ahead to a later section of the game. An unknown alien force had torn apart the flagship starship Normandy, the ship near collapse. Shepard issued an evacuation order, forcing Linara to head to the escape pods. Surrounded by chaos, Shepard slowly made his way through the fire to a doorway--and then the booming sound dropped out entirely, sucked away by the vacuum in Dead Space-style, leaving only the rasp of Shepard's desperate breathing.

Walking on the skin of the dying ship, Shepard eventually found shipmate Joker, who was attempting to save the craft. But following that moment, the enemy ship fired a massive beam weapon at the Normandy, violently splitting it down the seam. Shepard was knocked about in the fury, then was entirely jettisoned into space. The hero flailed about in space as his air leaked out from the wrecked spacesuit, then disappeared into the black.

BioWare ended the live demonstration there. Hudson didn't need to reiterate that Mass Effect 2 was indeed a darker sequel.