In an exchange on Twitter between Ryan Gordon and John Gibson, the President of Tripwire Interactive, there's now hope for seeing a Linux port of Red Orchestra 2. Gibson congratulated Gordon on getting Unreal Engine 3 to work on Linux and says that "we should talk" after Gordon mentioned "RO2."
Red Orchestra 2: Heroes of Stalingrad is the sequel to Red Orchestra: Ostfront 41-45. Red Orchestra 2 debuted in September of 2011 as a Windows-exclusive title that's powered by Unreal Engine 3. Red Orchestra 2 is a first-person shooter themed around World War 2, and in particular the Battle of Stalingrad. The game has been reviewed favourably and now there's hope of seeing it released on Linux.
Ryan Gordon has previously been involved with Tripwire Interactive where he ported Red Orchestra and Killing Floor to Linux. The original Red Orchestra along with Killing Floor are based upon Unreal Engine 2.5 with modifications, not UE3.