Several episodes of downloadable content (that explored the past of the protagonists) were planned, but only one was ever released: Heavy Rain: Chronicle One - The Taxidermist (2010), which featured Madison Paige. Future chronicles were put on indefinite hold to focus on adding Playstation Move support to the main game. It is highly unlikely that any more chronicles will be released.
Playable scenes where Ethan would have to navigate through nightmares in known locations while completely submerged through water, making it clear to the player of what Ethan's blackouts were like. Ethan's blackouts were also explained as being brought on by the Origami Killer, who had established a mental connection to Ethan at the event of his son's death. It was cut for pacing reasons, and because the cause gave a supernatural tone the game developers didn't want. There is still a reference in the final version of the game by Ethan's psychologist that he was suffering from nightmares of drowning.
Nearly all characters were modeled after the actors who lend their voices to the respective characters - some actors were French while others were English. For that they also done their own motion capturing, which makes the characters move so real.
In one of the Behind the Scenes videos Jacqui Ainsley is seen while auditioning for Madison. The dialog she read for Madison explained that while on assignment in the middle of war zone a terrorist attack took place and she felt responsibility since she was powerless to stop it. This would have explained to the player Post Traumatic Stress Disorder was the cause of her insomnia, but the monologue is not in the final version of the game.
A lot of scenes that fleshed out Madison were cut out. Scenes planned would've involved helping her redecorating her apartment (which looked different than in the final version). It was also planned that the newspaper she worked for was going to be a major set piece which would get multiple visits so she could do research and write her articles. It also would've established why she suffers from insomnia, which was because she had been a war corespondent.
The chapter 'Crime Scene' takes place on Tuesday, October 4th, 2011. This establishes that the main storyline takes place between Monday, October 3rd ('Father and Son'), to Friday, October 7th, 2011 ('The Old Warehouse'). The opening two chapters take place in 2009, and two other chapters take place in 1977.
When first announced at E3 2006 the game was intended to be multi-platform (PC, PS3 and Xbox 360). However the initial tech demo at E3 was done on Sony's PS3 development kits. The E3 crowd was so impressed by the real-time cinematic on Sony's hardware, it won best of show by some critics and generated a lot of buzz for the PS3. Sony eventually got exclusive rights to publishing the game.
Launch title for the Playstation Move. Although it was released months before the Move's release, the game was freely patched with native Move support before the launch of the Move, and all re-releases of the game since the Move's release have Playstation Move Support proudly displayed on the box.
A scene of Ethan taking his son Shaun to school after the 'Father and Son' chapter was cut, as it was just too much like the previous chapter. Ethan was originally supposed to get the letter from the Origami Killer in that scene. When the scene was cut, the letter was added to 'Father and Son' instead.
The trivia items below may give away important plot points.
The apartment that Ethan is moving into at the end of the game is the same apartment that was lived in by the hero of David Cage's last "interactive drama" game Indigo Prophecy (2005). Ethan even makes a funny comment about "a friend" helping him get it. That friend is Lucas Kane from the other game.
The Origami Killer was originally scripted to kill Ann Shephard after she talked to Madison. However the developers cut it because it didn't fit with the killer's motivations, and they figured with Ann's condition she would've just forgotten everything anyway.