Dear Return 2 Games Supporter!
Finally, we were able to introduce Supporter's Pack to Steam (as a separate package) which will make it easier for us to give you new games and DLC (when they are ready) directly through Steam.
This required us to make some changes to Humble Store. We will need you to redeem the key from Humble Store (you can find it both in Purchases and Keys but not in your Library) on Steam again. The new key should give you access to Return 2 Games Supporter's Pack product on Steam.
Let us know if you encounter any problems while doing this.
If you have already contacted us about your name in credits, please select "No thanks/Done already" in the appropriate pop-up window inside the game.
We're very sorry for the inconvenience - we hope this transition will go smoothly and we will have an easier way to give you new content when it's done.
Thing Trunk Team