Casey Hudson, Executive Producer on Mass Effect 2, has updated his blog at IGN with a general discussion on what was presented at E3 2009.
Of particular interest is the possibility for Commander Shepard and his squad members to permanently die. Hudson states "When you get to the very end of the story in Mass Effect 2, you will get one of a wide variety of climactic and satisfying endings. Depending on how prepared you were, your ending may involve Shepard making the ultimate sacrifice to accomplish the mission."
"Part of what makes the final mission dangerous in a more profound way is that each squad member could potentially die a real, story-based death during that mission as well.You might have an ending where Shepard’s entire team survives, or where the entire mission is a bloodbath and everyone (including Shepard) is killed, or anything in between."
Hudson continues "if your Shepard dies in the end of Mass Effect 2, that's the end of him / her. In that case, you can play Mass Effect 3 as “a” Shepard – just not “your” Shepard."
Hudson also discusses importing savegames from Mass Effect to Mass Effect 2. "The Mass Effect savegame doesn't just contain a couple of your big choices. It contains countless decisions you've made, both large and small. These things could each potentially carry forward and affect your story in Mass Effect 2."
Savegames that are able to affect a game's sequel, and in turn its sequel's sequel, opens up a new era of replayability for videogames. Unfortunately I lost all of my Mass Effect savegames. Looks like I'll have to play through it again.
Hudson concludes by answering some common questions including "Will Ashley/Garrus/Wrex/etc return in ME2?" and "Will there be alien love scenes?" The entire blog can be viewed here.