Here's a reason I usually tell you not to take SteamDB entries as confirmation of a Linux version. The Hard Reset Redux developers have stated it is not coming to Linux as it hasn't been popular enough for a port.
From the post:
QuoteI'm not aware of any plans to port HR to Steam. HR isn't popular enough to justify the Linux port.
A shame, but not everything works out in our favour.
Nothing to see here, move along, move along.