You have to do three things to get the Steam version of this game running:
- Run the game the first time. This will create the folder "BFBC2" in your documents folder. The game won't run, so you might have to force quit it.
- Open ~/Documents/BFBC2/settings.ini and change "DxVersion=auto" to "DxVersion=9" and "SpeakerCount=0" to "SpeakerCount=2"
- Choose "Run Command…" from the "Programs" menu in CrossOver Games and run the command "regedit". Make sure you use the right bottle. Then go to HKEY_CURRENT_USER\Software\Wine\DirectInput and create a new string value named "MouseWarpOverride" and set the value to "force"
I played through the first two missions and online. The game runs fine, but sometime it has some slowdowns. You cannot play on ranked multiplayer servers, because Punkbuster isn't working, but other servers work.