Ok, I just got finished watched the feature on Heavy Rain on GTTV. This is, by far, the most info we've seen for the game.
To start, the script for this game is apparently a massive 2,000+ words. We have two characters confirmed: Norman Jayden, a FBI investigator, and Madison Page, a reporter (She was the character from the demo reel).
One level was demoed on the show, a scene with Jayden as he investigates a junk yard owned by one mad black dude. Here we see the prompt system. It definitely looks like an evolved version of IP's system to me. When he has Mad Jack corner we see 5 or 6 options pop up for what to do all kind of chaotically scattered around him to signify his cluttered mind. It seems the emphasis is much more on speed then IP here. There was a part where he fought Mad Jack, and it seemed to me to be faster then IP. It might have just been the video.
Now, here's a very interesting tidbit. They've hit on this a little before, but there is no 'Game Over' in this game. When a character dies, you go to the next story of the next character and how and when the last character dies directly effects the story of the next character in line. Now, here's something that was interesting to me; when asked by Geoff if these stories happened simultaneously or in real time and if the characters path story would intercede and the guy kind of danced around it. Not sure if I misunderstand, but I kind of got the impression that the stories may end up happening in different time periods. That would make sense has to how dying with one character could effect the others, like he did or didn't get to do something that has major impacts on the future or something. Once again I may be reading too much in that, but it's a cool idea either way. The video at E3 will be focused on Madison, and possibly a reveal of the other two character
They talked that the game will be able to be stretched to your preference. If you wish, you can easily do the game in 4-6 hours, but you can also explore everything and touch on every little subplot to extend the game significantly. Replayability was something they stressed, for example, you can finish Jayden's story, but replay again to see how the other stories was effected by him dying at a certain point, say the Mad Jack part. Looks of possibilities if this ends up being accurate.
We were promised a game that 'pushed the limits' of the M-rating. Sex, violence, nudity, language, blah, blah, blah, blah. Either way, the game looked gorgeous.
Now, here is the not so good news. On the show that announced the game as coming out "next year". Now, to note, it was Geoff who said this, but it sounds to me that this will end up being a '10 title after all. Good footage, I would recommend checking it out when it comes up on GT's website