This update hopefully fixes an issue with the game failing to launch via Steam at all on Windows. With the switch to an x64 executable, the .exe name was switched from RCAST32.exe to RCAST64.exe , with the default launch option changed accordingly. However, this didn't seem to stick on some users' end, so the file name's been changed back to how it was from the get-go.
Nothing's changed with the game itself.