Sorry for the confusion... It will NOT play in INTERNATIONAL 360's unless they purchased an xbox from North America. I thought there was a to mod to make them to be region free but that doesn't look possible anyway.
North American Xbox systems will only play NTSC games, Japanese boxes will play NTSC-J games and Europe and the rest of the PAL territories will only play games marked with the PAL symbol is the general rule of thumb.
It's a Real time strategy... and some extra game details...
Content Download : Yes Co-op Mode : 2 co-op Leaderboards : Yes Number of Online Players : 2-4 Players Number of Players : 1 Player Resolution : HDTV 720/1080 Sound : Dolby Digital Voice : Yes Hard Drive Space : 2 MB to save game