But many of the fans savvy enough to seek it out are by now aware that Activity's ending wasn't always as it stands now. In fact, the film runs about ten minutes shorter between its late '07/early '08 festival screenings and its current cut.
So, to answer the questions that I and others fortunate enough to have seen the original version have been fielding, we'll be taking a look at as many differences as we can remember between the two, not to mention the further rumblings of what was different in test screenings for the film.
Naturally, this means spoilers. I know, it says as much right there in the headline, but for the sake of covering our butts, let's make this clear: a spoiler warning for everything post-jump.
There, that ought to do it.
I SAID SPOILERS!
The daytime differences: This is where I felt the film got its biggest improvement. The set-up is brisker and better now, the psychic shows up maybe a bit earlier and thus seems less arbitrary at making the wheels move when we're not in the bedroom, and the couple themselves are friskier and funnier (I'm pretty sure that Micah gets no sex in the original cut, whereas the camera is set on the nightstand here before being turned off for some hanky-panky). In this version, there are two added scenes, in which Katie's keys are heard thrown around at night and found on the floor the next morning, and an encounter with a broken picture and breath on Katie's neck, taking place in plain daylight and helping to up the ante as to when this entity is willing to mess with them.
In a recent interview with our Peter Hall, director Oren Peli said that they shot nearly 70 hours of footage originally and then went back to re-shoot stuff. I'd bet that any added relationship bits came from the original footage; any extra scares were re-shot scenes. Also: Katie's voice towards the end gets a digital touch-up to sound more possessed when she just wants to sleep all day and insists that everything is going to be okay.
The nighttime differences: I suspect that some of the attacks were shuffled around in order to build more in terms of intensity. Most notable was that the sheet on their bed rising and falling took place around the 70-minute mark now, on the night before Katie gets dragged. I'm fairly certain that bit took place much earlier in the original cut, maybe a half-hour in, but it makes more sense as placed here.
Also: each scene where the demon enters the bedroom is now accompanied by an obviously ominous rumbling on the film's soundtrack, serving as a Pavlovian cue for audiences to stop texting and sit up.
The current ending: Every version of the climax that I've heard about has Micah dashing downstairs after Katie is dragged out of the bed/room, where some sort of off-screen ruckus takes place and only a bloody Katie returns. In this version, Katie tosses Micah's body at the camera from the hallway (a great money shot, I'll admit, albeit one given away in the trailer), kneels down beside his body to either sniff or lick it, and then approaches the camera before smiling and then lunging at the lens. A title card informs us that Micah's body was found on whatever date, and that Katie's whereabouts are still unknown...
A little too Hollywood cliffhanger-y for my tastes, but it plays better on the screen than I'd heard.
The original ending: This time, Micah stays downstairs as Katie returns to the bedroom, covered in blood and now holding a knife. She proceeds to rock on the floor next to the bed for something like two days straight.* We hear a friend (the girl who offered that Katie stay at her place, I'm guessing) leave a message on their answering machine, wondering where they are. She later stops by, presumably finds Micah dead downstairs, screams and leaves. The police then show up later, with Katie only awakening from her catatonic state as they come up the stairs, with guns drawn. She's covered in blood, holding a knife and very confused as to what's going on, and so the officers proceed to fire on her. The title card then dedicates the film to the couple's memory.
This one is a bit anti-climactic, yes, but I think it's a bit more tragic that Katie's been tormented all her life, only to face an unwitting death such as this.
The alternate ending(s): Now, several endings were shot after the film was picked up. The only one of those that I've seen described anywhere was screened maybe once at a test screening, and Peli suggests that we may see it yet on the DVD. In this version, Micah dies downstairs, bloody Katie returns to the bedroom with knife in hand, and she proceeds to slit her own throat in front of the camera (without looking right into it).
I personally prefer this one because Micah makes a gesture with a knife in the kitchen very early on, suggesting that whatever the problem is, they'll [slicing motion] take care of it. That might've made for a nice bookend, and would've been disturbing regardless.
*The trailer shows a shot of this as well. That's right -- they used a bit from both endings to promote the film.
UPDATE! (10/28/09) Here's the original ending!