Zombie Kill of the Week - Reborn is a challenging, fast paced, 2D survival shooter! Featuring a compelling single player survival mode and cooperative multiplayer for up-to four players, this is one zombie firefight you're not going to want to miss!
Open the Steam client, login and locate the Games tab on the top menu. Click this and then select “Activate a Product on Steam…”
Enter your unique code that's displayed on the 'Orders' page of CDKeys.com and follow the prompts to activate.
Your game is now viewable in the “Library” tab and is available to download/install when you’re ready. You can find additional support for the Steam client here: https://help.steampowered.com/en/wizard/HelpWithSteam