The first ever public playtest for Goblin and Coins II will happen between May 15th and 30th of this year right here on Steam. It's completely free for you to participate, just request access on the store page at any time during this period and you'll get notified when you can download and test the game.
(Find this widget on the game page and click the green button)
More info on what is available in the current build for you to see, try out and provide feedback, how to do it, where to write of your experience and all of that cam be found if you click here.