Apparently, greedfall is released on September 10, 2019.
@Sulfur Well, Some game have a bonus for anyone who pre purchase. That's include Greedfall too.
Greedfall give adventure gear DLC for pre purchase. That DLC may available to buy after game release but you have to pay additional $ for them.
Some game also available to pre download before game release. That mean you don't have to wait for hour/risk for server down while downloading game.
For me I usually pre order game that I absolutely sure to play it at day1. Especially if they give some bonus to me.