RUNNING WITH RIFLES: PACIFIC, the World War II themed expansion for RUNNING WITH RIFLES, the damn fun top-down tactical shooter has a release date and trailer.
Hiveswap: Act 1, based on the popular, long-running webcomic Homestuck by Andrew Hussie, has released for Linux, just over 1 month following release of the Windows and Mac versions.
The developer of The First Tree emailed in to let everyone know that their beautiful 3rd-person exploration game is now on Linux 'due to a ton of requests'.
Continuing on from the first part, Estranged: Act II is now available on Linux. The developer switched from Source to Unreal Engine for the second part as well.
I came across HEADLINER today while researching more potential Linux games, this adventure game sees you controlling the news to further your goals. It might come to Linux, as the developer is looking into it.