Why would it be stretched? There are plenty of games that are only rendered in 16:9 that put black bars on my 16:10 display. I can't remember the last one that didn't do it itself, and if that was the case my GPU can do it. And if my GPU couldn't do it, my monitor could.
Yes, it's rendered at 16:9 @ 1080p but looks awful when scaled up to 2560x1440. Anyway, I'm just playing it in a window right now, but 30 mins in and I'm already wishing I had got it on my PS4.
The game itself is great though so far. I'm loving it.