I realize I’m quite late in checking for my steam key, but I’ve yet to receive one. I’ve emailed both Fastspring and the support address to no avail. Please help!
http://forum.greenheartgames.com/t/faq-game-dev-tycoon-steam-keys/6728
Please post your issue in here
me to 
Hey Guys,
All emails sent to support@greenheartgames.com have been answered. Please check your email and spam folders for a reply from myself or fastspring.
I havent recieved it either. Same with me im quite late, but none have answered when i send them an email, and i never got the steam key.
Please send me an email to support@greenheartgames.com and let me know which store your purchased from and your order number if you have it.