Last Fortress Underground codes are unique codes shared by developers on their official social media handles, including Facebook, Twitter, Reddit, Discord, Instagram, and YouTube. They are also shared on the game's forum website. These codes reward in-game currencies or items, usually the basic or premium currency. You can only use a Last Fortress Underground code once per account. If you've already redeemed a code, it won't work, and the game will display a message saying you've already redeemed the gift code. Some codes are permanent, while others are time-sensitive or limited to a certain number of attempts. Permanent codes can be redeemed at any time, while time-sensitive codes have a limited time frame for redemption. New codes are released at different times, depending on the game developers. Some developers release new codes weekly, on weekends, Mondays, or Fridays, while others release them on festive dates like holidays and special events. There is no prior requirement to redeem Last Fortress Underground codes; you can redeem them as long as they are active.