Plenty of reasons it's sold poorly.
-Advertising (was there any?)
-Launching next to Red Dead a 7 million selling juggernaut.
-It's critical reception, many had it pegged as AAA and it ended up getting much lower scores then people expected.
-It's genre.
-A new IP.
-Apathy over 5 years of announcements.
I know many posters already posted this, just summarizing.
I think had Remedy got the title to market faster, perhaps focusing less on the engine, had MS backed the title with some solid advertising and had it launched in a better release window in an even quieter part of the year it could be sitting on 2m sales right now.
It does remind me a little of Uncharted: DF though, a solid game with all the foundations that could potentially have an amazing sequel.
