The original 2011 demo of Prey 2 at E3 had a lot of people excited about the game, but it never came to fruition. Bethesda and Human Head Studios ended up parting ways over the game, but some new information has released indicating that the game could have been pretty awesome.
The general gist centered around the theme that Killian would be retrieving bounties, while also under the impression that he was the only human on Exodus. It turns out that that isn't true at all. It turns out that Tommy, the hero from the original Prey, also happens to be on the planet Exodus.
Tommy communicates with Killian through his spirit form because his body happens to be trapped by an unknown entity, so it's up to Killian to go and rescue him.
The twist would be discovered that the whole planet of Exodus was actually being controlled by a group known as The Keepers, and they would end up being the true enemies in Prey 2.
The real plot twist in the game is that Killian's physical presence is actually a clone.
It turns out he's been dying hundreds and hundreds (possibly thousands) of times over the course of the ten years since his plane crashed, and every time he dies his consciousness respawns into a new physical clone.
Additionally, Killian and Tommy have actually met many times before, but Killian doesn't remember because he would usually end up dying and respawning in his safe house.
*Minor (or major) spoilers ahead. *This is the exact same plot twist that was used in the game Soma, the underwater horror title from Frictional Games. It turns out that the protagonist and another character are constantly moving their consciousness into new physical bodies, clones. They did this either when they were about to die or in order to reach some new place that couldn't be reached in their current physical form. However, the trippy part about Soma was that the consciousness never left the old body, it just duplicated into a new one. So any pain, suffering, horrible death, or other ailment that was about to or would have befallen the characters before the consciousness transfer would still be felt and realized by the duplicate consciousness.
In the case of Prey 2, Killian loses his memory and doesn't remember every time he's died. However, this twist is further detailed near the end of the game where he discovers a pathway of his own dead bodies, similar to that infamous scene on the upper deck of the boat in the movie Triangle.
The twist was supposed to be a meta-commentary on the whole nature of respawning in games. There was even supposed to be a hardcore mode where players would have to purchase credits in order to respawn. But it gets even more meta than that!
It's outlined in the video below if you have time to check it out.
If you don't have time to check it out, essentially after destroying the Keeper's war sphere (which they were planning on using to attack Earth), Killian blasts out of the facility and into outer space. Before succumbing to the harsh realities (and death) of space, Killian uses his bounty capture teleportation device and inputs random coordinates, which actually takes him back to Earth. He lives out a happy life and then grows old. In the meantime the credits are rolling.
However, there's one more twist. On his death bed, Killian eventually passes from old age... and the screen fades to white once the Prey 2 credits end. The screen then goes to a loading screen and it reloads Killian's apartment where the clones are, and his consciousness reconnects to another clone and players can continue to explore the open world of Exodus.