Recoil Games appear to have filed for bankruptcy a while ago and sadly a casualty of that is their game Rochard, which has now been removed for sale.
Rochard was an award-winning side-scroller puzzle-platformer, originally released in 2011. It was also part of the early indie game push for Linux, thanks to it being part of the Humble Indie Bundle 6 back in 2012 it was ported to Linux especially for the bundle. Not only that, it was also one of the first commercial Unity games (possibly the actual first) to be built for Linux too, so it holds something of a special place in our history.
Sadly, you can no longer buy it officially.
In a short announcement post on Steam, the developer said this:
Recoil Games has applied for bankruptcy quite a while ago. We've been trying hard to find a new home for the game. Unfortunately there were no offers that would have enabled the bankruptcy estate to close the deal. The bankruptcy estate will soon be closed and the publishing agreement with Steam will be terminated.
This means Rochard can no longer be purchased on Steam. However, the game will remain available in your Steam libraries as is.