This 'looks' like my cup of tea but I'm really not sure.
Is this an open world/sandbox game ? An adventure ? Stealth game ?
I really can't tell from the description or trailers.
Also how much content is in already and how much is planned ?
This is a Game in development. That means that we are working on it for another few months before full release.
There is maybe 40% of the final content. 1 playable character out of 3 and 3 out 5 islands. No story but the prologue that you may have seen from E3 Microsoft press conference.
However, there are a lot of encounters (quests), the world is procedurally-generated so none of your playthroughs will be exactly the same.
The game takes place in a dystopian 1960s England where everybody is using a drug called Joy to feel happy. You will play as Arthur who tries to escape this society.
There are survival elements, as well as combat and conformity. You will have to chose your play style.