"Who said stealth had to be so SLOW? Introducing Stealth Bastard – the game that injects a syringe-full-o'-adrenaline and a liberal dash of bastard-hardness into the hide-em-up. Not only that, but you can also create your own levels using the built-in editor and share them with the world!"Go to: http://store.steampowered.com/ and download STEAM client
Click “Install Steam” (from the upper right corner)
Install and start application, login with your Account name and Password (create one if you don’t have).
Please follow these instructions to activate a new retail purchase on Steam:
Launch Steam and log into your Steam account.
Click the Games Menu.
Choose Activate a Product on Steam…
Follow the onscreen instructions to complete the process.
After successful code verification go to the “MY GAMES” tab and start downloading.