https://store.steampowered.com/app/2709300/After_War_Town
"In the heart-pounding virtual battleground of 'After War Town,' immerse yourself in a gripping shooter experience where the fate of a besieged city lies in your hands.

INSTRUCTION FOR ACTIVATION:

1. You must download and install Steam http://steampowered.com/download/SteamInstall.msi
2. Log in to your account or register a new one.
3. Go to the "My Games" section and select "Activate via Steam ..." and enter the key received after payment.
4. After activation, the game will appear in the list of games (Library) and you can download it