Hello everyone!
Not a Duck isn't out yet, but you can already grab a free Steam key on SteamGameKey, a new site where developers hand keys straight to players.
How to get your key
Open the link at the bottom of this post
Sign in with your Steam account (no sign-up form, no email)
Open the case and your key appears right away
Activate it on Steam and the game unlocks in your library on launch day
One key per Steam account, while keys last.
And don't forget to add it to your wishlist so you know the moment it launches!