I suggest you to push open source tag more on steam. Free to play is currently like cancer and more like pay to win. Open source tag brings quality crowd.
PS you cant install on linux from steam?
And one more thing these DLC looks like "cancer" I understand what these actually are, but that button buy all and DLC in general gives bad first impression. You have to write clearly that it is completely optional and not needed and doesnt impact gameplay in any way very clearly. From first glance even to me it wasnt clear.