Editing your post to be just the broken support link.
Capsized went live yesterday, Dear Esther is likely waiting for the native port being developed atm - https://twitter.com/icculus/status/339463775876964352
Hello @Naddiseo, this url appears to have been fixed some time ago.
If you encounter the invalid platform error and the game claims support for your OS, then this should be brought to the game's devs on a per-game basis.
Nothing extracted yet.
I'm currently putting in the steam codes from the latest HB, but I get "An error occurred while installed (invalid platform)".
Additionally, the link provided gives the following error