timppu: Sure, why not. The requirement is that you subscribe to the HB newsletter in order to get the game, but I have apparently subscribed to it already so even that was covered.
The nice thing also was that this was the Endless Space Collection, apparently including all the DLCs. I guess this is kind of a promotion to the sequel, Endless Space 2?
If it turns out to be a good game, I'd probably be willing to pay money on GOG for it. Wouldn't be the first time I buy on GOG for something I got for free from Steam earlier (or Origin or UPlay or or or...).
ES 2 is 75% off on Humble. It's promotion for the new ES2 DLC.