Doomspire

Doomspire is an epic, roguelike adventure card game set in the Doomspire, an ancient and cursed structure that spirals down into the abyss. Once a towering monument that pierced the heavens, the Doomspire now crumbles inward, its roots descending into darkness, where doom awaits all who descend. You will create your hero and venture deeper into the Doomspire, facing terrifying bosses, uncovering forgotten treasures, and battling for your very survival.

Open your Steam client, click "Games" in the top menu and choose "Activate a Product on Steam…"

Follow the on-screen instructions and insert your key.