There has been worry and speculation on the internet about the PS4 exclusivity that we announced during the press conference, so here are some details to help answer those questions.
Our deal with Sony is a limited-time exclusivity that applies to competing console platforms. Basically it is that you will see the game on the PlayStation 4 for a while before you will see it on the Wii U or the rumored next Microsoft console. (We haven't been disclosed on Microsoft's next console, so I don't know anything about that platform besides the rumors that are on the internet).
This exclusivity does not prevent us from being on the PC or iOS at launch, for example.
People have been speculating that we got paid for PS4 exclusivity, but that is not the case. There was no money involved.
The real situation is that, because we are a small developer, we only have the ability to launch on a small number of platforms at once. We liked the idea of being on a console, and originally we thought we might be on the PS3 or Xbox 360, but eventually we decided not to target either of those, due to the relatively low system specs and the work required to do the ports. After some more time went by, and our release date drifted further into the future, we realized that the next-generation console launch time might be a good time to release the game. (For a while we were hoping to be out substantially earlier than the next consoles, e.g. right now, so we didn't start thinking seriously about this until recently).
To launch a high-spec version of the game on a console, it came down to a choice between the next Microsoft console or the next Sony console. There were people at Sony who really liked the game and were keeping in touch with us about it, and so we naturally started going to their PS4 developer events, got a dev kit, and started playing with it. I don't have good communication with anyone at Microsoft right now, but all our technical people like the PS4 specs a lot more than the leaked Durango specs, and we like the positioning of the PS4 (it's about games) more than what we perceive Microsoft's positioning is going to be.
So we just found ourselves doing a PS4 port. And once we are doing that, it is not practical for us also to think about another console port. We were going to be a de facto console exclusive for Sony no matter what. As I mentioned, there are people at Sony who are very interested in The Witness, so they somehow percolated up through the ranks the idea of showing the game in the launch show.
Of course, Sony wants that show to point out things that are going to be exclusive or special to their console. If we are in their show, but next week we turn around and announce "we changed our mind, we are exclusive on Durango forever," that would be a bit weird. So to be in the show we signed a timed exclusivity for competing consoles. But this was just a formalization of something that was already going to be the case. We like the PS4 and we like the people at Sony we are working with, so it was an easy choice to make the agreement.
Exact timing of our release on launch platforms has yet to be figured out. It just depends on how much we can do and when; we'll know more as we get much closer to the game being done.