First Flight #45: Last Man Standing Game

Contest Details

Starts: July 31, 2025 Noon UTC

Ends: August 06, 2025 Noon UTC

Stats

nSLOC: 181

About the Project

The Last Man Standing Game is a decentralized "King of the Hill" style game implemented as a Solidity smart contract on the Ethereum Virtual Machine (EVM). It creates a competitive environment where players vie for the title of "King" by paying an increasing fee. The game's core mechanic revolves around a grace period: if no new player claims the throne before this period expires, the current King wins the entire accumulated prize pot.

Actors

This protocol includes the following roles:

1. Owner (Deployer)

Powers:

• Deploys the Game contract.
• Can update game parameters: gracePeriod, initialClaimFee, feeIncreasePercentage, platformFeePercentage.
• Can resetGame() to start a new round after a winner has been declared.
• Can withdrawPlatformFees() accumulated from claims. Limitations:
• Cannot claim the throne if they are already the current king.
• Cannot declare a winner before the grace period expires.
• Cannot reset the game if a round is still active.

2. King (Current King)

Powers:

• The last player to successfully claimThrone().
• Receives a small payout from the next player's claimFee (if applicable).
• Wins the entire pot if no one claims the throne before the gracePeriod expires.
• Can withdrawWinnings() once declared a winner. Limitations:
• Must pay the current claimFee to become king.
• Cannot claim the throne if they are already the current king.
• Their reign is temporary and can be overthrown by any other player.

3. Players (Claimants)

Powers:

• Can claimThrone() by sending the required claimFee.
• Can become the currentKing.
• Can potentially win the pot if they are the last king when the grace period expires. Limitations:
• Must send sufficient ETH to match or exceed the claimFee.
• Cannot claim if the game has ended.
• Cannot claim if they are already the current king.

4. Anyone (Declarer)

Powers:

• Can call declareWinner() once the gracePeriod has expired. Limitations:
• Cannot declare a winner if the grace period has not expired.
• Cannot declare a winner if no one has ever claimed the throne.
• Cannot declare a winner if the game has already ended.

Scope

src/
└── Game.sol

Compatibilities

Blockchains:

• Any EVM-compatible chain (e.g., Ethereum Mainnet, Sepolia, Arbitrum, Avalanche, Polygon) Tokens:
• ETH (native currency of the blockchain)

Setup

First, clone the project repository and install dependencies.

git clone https://github.com/CodeHawks-Contests/2025-07-last-man-standing.git
cd 2025-07-last-man-standing
forge install OpenZeppelin/openzeppelin-contracts
forge install foundry-rs/forge-std
forge build

None reported!