A blockchain is a distributed ledger in which participants who do not fully trust each other agree on the ledger’s content by running a consensus algorithm. It has been more popular and mature in recent years. Smart contracts on the blockchain system are usually redundantly executed by a large number of nodes for the purpose of verification, which can result in a large waste of computation. The waste is especially significant when the smart contracts are heavy-duty. The problem of reducing the computation has attracted a lot of interest from both the research community and the industry. In this creative component, we present a game theoretic design for efficient execution of heavy-duty smart contracts, and develop a simulator to implement the design and evaluate its performance in a large-scale blockchain system that simulates Ethereum. The simulator is built based on BlockSim, an emerging general-purpose blockchain simulator, but has enhanced it with detailed simulation of the heavy-duty smart contract protocol. The simulation results demonstrate the efficacy and efficiency of our design.