Steam redeemable key.
Cannot be redeemed in the following regions: Australia (AU), Cuba (CU), Germany (DE), Japan (JP), New Zealand (NZ), Sudan (SD), Singapore (SG), Syria (SY), Yemen (YE).
Note that you may face difficulties running the game on a modern system and might need a community-made patch, as the game was designed for Windows 2000 and Windows XP.